Merge remote-tracking branch 'origin/master' into flake-substitution

src/external-api-docs/doxygen.cfg.in

@@ -56,3 +56,5 @@ GENERATE_TREEVIEW = YES
 OPTIMIZE_OUTPUT_FOR_C  = YES
 
 USE_MDFILE_AS_MAINPAGE = doc/external-api/README.md
+
+QUIET = YES

src/internal-api-docs/doxygen.cfg.in

@@ -41,21 +41,21 @@ INPUT                  = \
   @src@/libcmd \
   @src@/libexpr \
   @src@/libexpr/flake \
-  @src@/nix-expr-tests \
-  @src@/nix-expr-tests/value \
-  @src@/nix-expr-test-support/test \
-  @src@/nix-expr-test-support/test/value \
+  @src@/libexpr-tests \
+  @src@/libexpr-tests/value \
+  @src@/libexpr-test-support/test \
+  @src@/libexpr-test-support/test/value \
   @src@/libexpr/value \
   @src@/libfetchers \
   @src@/libmain \
   @src@/libstore \
   @src@/libstore/build \
   @src@/libstore/builtins \
-  @src@/nix-store-tests \
-  @src@/nix-store-test-support/test \
+  @src@/libstore-tests \
+  @src@/libstore-test-support/test \
   @src@/libutil \
-  @src@/nix-util-tests \
-  @src@/nix-util-test-support/test \
+  @src@/libutil-tests \
+  @src@/libutil-test-support/test \
   @src@/nix \
   @src@/nix-env \
   @src@/nix-store
@@ -97,3 +97,6 @@ EXPAND_AS_DEFINED      = \
   DECLARE_WORKER_SERIALISER \
   DECLARE_SERVE_SERIALISER \
   LENGTH_PREFIXED_PROTO_HELPER
+
+WARN_IF_UNDOCUMENTED = NO
+QUIET = YES

src/libexpr-test-support/.version

@@ -0,0 +1 @@
+../../.version

src/libexpr-test-support/build-utils-meson

@@ -0,0 +1 @@
+../../build-utils-meson

src/libexpr-test-support/local.mk

@@ -0,0 +1,23 @@
+libraries += libexpr-test-support
+
+libexpr-test-support_NAME = libnixexpr-test-support
+
+libexpr-test-support_DIR := $(d)
+
+ifeq ($(INSTALL_UNIT_TESTS), yes)
+  libexpr-test-support_INSTALL_DIR := $(checklibdir)
+else
+  libexpr-test-support_INSTALL_DIR :=
+endif
+
+libexpr-test-support_SOURCES := \
+    $(wildcard $(d)/tests/*.cc) \
+    $(wildcard $(d)/tests/value/*.cc)
+
+libexpr-test-support_CXXFLAGS += $(libexpr-tests_EXTRA_INCLUDES)
+
+libexpr-test-support_LIBS = \
+    libstore-test-support libutil-test-support \
+    libexpr libstore libutil
+
+libexpr-test-support_LDFLAGS := $(THREAD_LDFLAGS) -lrapidcheck

src/libexpr-test-support/meson.build

@@ -0,0 +1,76 @@
+project('nix-expr-test-support', 'cpp',
+  version : files('.version'),
+  default_options : [
+    'cpp_std=c++2a',
+    # TODO(Qyriad): increase the warning level
+    'warning_level=1',
+    'debug=true',
+    'optimization=2',
+    'errorlogs=true', # Please print logs for tests that fail
+  ],
+  meson_version : '>= 1.1',
+  license : 'LGPL-2.1-or-later',
+)
+
+cxx = meson.get_compiler('cpp')
+
+subdir('build-utils-meson/deps-lists')
+
+deps_private_maybe_subproject = [
+]
+deps_public_maybe_subproject = [
+  dependency('nix-util'),
+  dependency('nix-util-test-support'),
+  dependency('nix-store'),
+  dependency('nix-store-test-support'),
+  dependency('nix-expr'),
+]
+subdir('build-utils-meson/subprojects')
+
+subdir('build-utils-meson/threads')
+
+rapidcheck = dependency('rapidcheck')
+deps_public += rapidcheck
+
+add_project_arguments(
+  # TODO(Qyriad): Yes this is how the autoconf+Make system did it.
+  # It would be nice for our headers to be idempotent instead.
+  '-include', 'config-util.hh',
+  '-include', 'config-store.hh',
+  '-include', 'config-expr.hh',
+  language : 'cpp',
+)
+
+subdir('build-utils-meson/diagnostics')
+
+sources = files(
+  'tests/value/context.cc',
+)
+
+include_dirs = [include_directories('.')]
+
+headers = files(
+  'tests/libexpr.hh',
+  'tests/nix_api_expr.hh',
+  'tests/value/context.hh',
+)
+
+subdir('build-utils-meson/export-all-symbols')
+
+this_library = library(
+  'nix-expr-test-support',
+  sources,
+  dependencies : deps_public + deps_private + deps_other,
+  include_directories : include_dirs,
+  # TODO: Remove `-lrapidcheck` when https://github.com/emil-e/rapidcheck/pull/326
+  #       is available. See also ../libutil/build.meson
+  link_args: linker_export_flags + ['-lrapidcheck'],
+  prelink : true, # For C++ static initializers
+  install : true,
+)
+
+install_headers(headers, subdir : 'nix', preserve_path : true)
+
+libraries_private = []
+
+subdir('build-utils-meson/export')

src/libexpr-test-support/package.nix

@@ -0,0 +1,60 @@
+{ lib
+, stdenv
+, mkMesonLibrary
+
+, nix-store-test-support
+, nix-expr
+
+, rapidcheck
+
+# Configuration Options
+
+, version
+}:
+
+let
+  inherit (lib) fileset;
+in
+
+mkMesonLibrary (finalAttrs: {
+  pname = "nix-util-test-support";
+  inherit version;
+
+  workDir = ./.;
+  fileset = fileset.unions [
+    ../../build-utils-meson
+    ./build-utils-meson
+    ../../.version
+    ./.version
+    ./meson.build
+    # ./meson.options
+    (fileset.fileFilter (file: file.hasExt "cc") ./.)
+    (fileset.fileFilter (file: file.hasExt "hh") ./.)
+  ];
+
+  propagatedBuildInputs = [
+    nix-store-test-support
+    nix-expr
+    rapidcheck
+  ];
+
+  preConfigure =
+    # "Inline" .version so it's not a symlink, and includes the suffix.
+    # Do the meson utils, without modification.
+    ''
+      chmod u+w ./.version
+      echo ${version} > ../../.version
+    '';
+
+  mesonFlags = [
+  ];
+
+  env = lib.optionalAttrs (stdenv.isLinux && !(stdenv.hostPlatform.isStatic && stdenv.system == "aarch64-linux")) {
+    LDFLAGS = "-fuse-ld=gold";
+  };
+
+  meta = {
+    platforms = lib.platforms.unix ++ lib.platforms.windows;
+  };
+
+})

src/libexpr-test-support/tests/libexpr.hh

@@ -0,0 +1,150 @@
+#pragma once
+///@file
+
+#include <gtest/gtest.h>
+#include <gmock/gmock.h>
+
+#include "fetch-settings.hh"
+#include "value.hh"
+#include "nixexpr.hh"
+#include "nixexpr.hh"
+#include "eval.hh"
+#include "eval-gc.hh"
+#include "eval-inline.hh"
+#include "eval-settings.hh"
+
+#include "tests/libstore.hh"
+
+namespace nix {
+    class LibExprTest : public LibStoreTest {
+        public:
+            static void SetUpTestSuite() {
+                LibStoreTest::SetUpTestSuite();
+                initGC();
+            }
+
+        protected:
+            LibExprTest()
+                : LibStoreTest()
+                , state({}, store, fetchSettings, evalSettings, nullptr)
+            {
+                evalSettings.nixPath = {};
+            }
+            Value eval(std::string input, bool forceValue = true) {
+                Value v;
+                Expr * e = state.parseExprFromString(input, state.rootPath(CanonPath::root));
+                assert(e);
+                state.eval(e, v);
+                if (forceValue)
+                    state.forceValue(v, noPos);
+                return v;
+            }
+
+            Symbol createSymbol(const char * value) {
+                return state.symbols.create(value);
+            }
+
+            bool readOnlyMode = true;
+            fetchers::Settings fetchSettings{};
+            EvalSettings evalSettings{readOnlyMode};
+            EvalState state;
+    };
+
+    MATCHER(IsListType, "") {
+        return arg != nList;
+    }
+
+    MATCHER(IsList, "") {
+        return arg.type() == nList;
+    }
+
+    MATCHER(IsString, "") {
+        return arg.type() == nString;
+    }
+
+    MATCHER(IsNull, "") {
+        return arg.type() == nNull;
+    }
+
+    MATCHER(IsThunk, "") {
+        return arg.type() == nThunk;
+    }
+
+    MATCHER(IsAttrs, "") {
+        return arg.type() == nAttrs;
+    }
+
+    MATCHER_P(IsStringEq, s, fmt("The string is equal to \"%1%\"", s)) {
+        if (arg.type() != nString) {
+            return false;
+        }
+        return std::string_view(arg.c_str()) == s;
+    }
+
+    MATCHER_P(IsIntEq, v, fmt("The string is equal to \"%1%\"", v)) {
+        if (arg.type() != nInt) {
+            return false;
+        }
+        return arg.integer().value == v;
+    }
+
+    MATCHER_P(IsFloatEq, v, fmt("The float is equal to \"%1%\"", v)) {
+        if (arg.type() != nFloat) {
+            return false;
+        }
+        return arg.fpoint() == v;
+    }
+
+    MATCHER(IsTrue, "") {
+        if (arg.type() != nBool) {
+            return false;
+        }
+        return arg.boolean() == true;
+    }
+
+    MATCHER(IsFalse, "") {
+        if (arg.type() != nBool) {
+            return false;
+        }
+        return arg.boolean() == false;
+    }
+
+    MATCHER_P(IsPathEq, p, fmt("Is a path equal to \"%1%\"", p)) {
+        if (arg.type() != nPath) {
+            *result_listener << "Expected a path got " << arg.type();
+            return false;
+        } else {
+            auto path = arg.path();
+            if (path.path != CanonPath(p)) {
+                *result_listener << "Expected a path that equals \"" << p << "\" but got: " << path.path;
+                return false;
+            }
+        }
+        return true;
+    }
+
+
+    MATCHER_P(IsListOfSize, n, fmt("Is a list of size [%1%]", n)) {
+        if (arg.type() != nList) {
+            *result_listener << "Expected list got " << arg.type();
+            return false;
+        } else if (arg.listSize() != (size_t)n) {
+            *result_listener << "Expected as list of size " << n << " got " << arg.listSize();
+            return false;
+        }
+        return true;
+    }
+
+    MATCHER_P(IsAttrsOfSize, n, fmt("Is a set of size [%1%]", n)) {
+        if (arg.type() != nAttrs) {
+            *result_listener << "Expected set got " << arg.type();
+            return false;
+        } else if (arg.attrs()->size() != (size_t) n) {
+            *result_listener << "Expected a set with " << n << " attributes but got " << arg.attrs()->size();
+            return false;
+        }
+        return true;
+    }
+
+
+} /* namespace nix */

src/libexpr-test-support/tests/nix_api_expr.hh

@@ -0,0 +1,31 @@
+#pragma once
+///@file
+#include "nix_api_expr.h"
+#include "nix_api_value.h"
+#include "tests/nix_api_store.hh"
+
+#include <gtest/gtest.h>
+
+namespace nixC {
+
+class nix_api_expr_test : public nix_api_store_test
+{
+protected:
+
+    nix_api_expr_test()
+    {
+        nix_libexpr_init(ctx);
+        state = nix_state_create(nullptr, nullptr, store);
+        value = nix_alloc_value(nullptr, state);
+    }
+    ~nix_api_expr_test()
+    {
+        nix_gc_decref(nullptr, value);
+        nix_state_free(state);
+    }
+
+    EvalState * state;
+    nix_value * value;
+};
+
+}

src/libexpr-test-support/tests/value/context.cc

@@ -0,0 +1,30 @@
+#include <rapidcheck.h>
+
+#include "tests/path.hh"
+#include "tests/value/context.hh"
+
+namespace rc {
+using namespace nix;
+
+Gen<NixStringContextElem::DrvDeep> Arbitrary<NixStringContextElem::DrvDeep>::arbitrary()
+{
+    return gen::just(NixStringContextElem::DrvDeep {
+        .drvPath = *gen::arbitrary<StorePath>(),
+    });
+}
+
+Gen<NixStringContextElem> Arbitrary<NixStringContextElem>::arbitrary()
+{
+    switch (*gen::inRange<uint8_t>(0, std::variant_size_v<NixStringContextElem::Raw>)) {
+    case 0:
+        return gen::just<NixStringContextElem>(*gen::arbitrary<NixStringContextElem::Opaque>());
+    case 1:
+        return gen::just<NixStringContextElem>(*gen::arbitrary<NixStringContextElem::DrvDeep>());
+    case 2:
+        return gen::just<NixStringContextElem>(*gen::arbitrary<NixStringContextElem::Built>());
+    default:
+        assert(false);
+    }
+}
+
+}

src/libexpr-test-support/tests/value/context.hh

@@ -0,0 +1,31 @@
+#pragma once
+///@file
+
+#include <rapidcheck/gen/Arbitrary.h>
+
+#include "value/context.hh"
+
+namespace rc {
+using namespace nix;
+
+template<>
+struct Arbitrary<NixStringContextElem::Opaque> {
+    static Gen<NixStringContextElem::Opaque> arbitrary();
+};
+
+template<>
+struct Arbitrary<NixStringContextElem::Built> {
+    static Gen<NixStringContextElem::Built> arbitrary();
+};
+
+template<>
+struct Arbitrary<NixStringContextElem::DrvDeep> {
+    static Gen<NixStringContextElem::DrvDeep> arbitrary();
+};
+
+template<>
+struct Arbitrary<NixStringContextElem> {
+    static Gen<NixStringContextElem> arbitrary();
+};
+
+}

src/libexpr-tests/.version

@@ -0,0 +1 @@
+../../.version

src/libexpr-tests/build-utils-meson

@@ -0,0 +1 @@
+../../build-utils-meson

src/libexpr-tests/derived-path.cc

@@ -0,0 +1,68 @@
+#include <nlohmann/json.hpp>
+#include <gtest/gtest.h>
+#include <rapidcheck/gtest.h>
+
+#include "tests/derived-path.hh"
+#include "tests/libexpr.hh"
+
+namespace nix {
+
+// Testing of trivial expressions
+class DerivedPathExpressionTest : public LibExprTest {};
+
+// FIXME: `RC_GTEST_FIXTURE_PROP` isn't calling `SetUpTestSuite` because it is
+// no a real fixture.
+//
+// See https://github.com/emil-e/rapidcheck/blob/master/doc/gtest.md#rc_gtest_fixture_propfixture-name-args
+TEST_F(DerivedPathExpressionTest, force_init)
+{
+}
+
+#ifndef COVERAGE
+
+RC_GTEST_FIXTURE_PROP(
+    DerivedPathExpressionTest,
+    prop_opaque_path_round_trip,
+    (const SingleDerivedPath::Opaque & o))
+{
+    auto * v = state.allocValue();
+    state.mkStorePathString(o.path, *v);
+    auto d = state.coerceToSingleDerivedPath(noPos, *v, "");
+    RC_ASSERT(SingleDerivedPath { o } == d);
+}
+
+// TODO use DerivedPath::Built for parameter once it supports a single output
+// path only.
+
+RC_GTEST_FIXTURE_PROP(
+    DerivedPathExpressionTest,
+    prop_derived_path_built_placeholder_round_trip,
+    (const SingleDerivedPath::Built & b))
+{
+    /**
+     * We set these in tests rather than the regular globals so we don't have
+     * to worry about race conditions if the tests run concurrently.
+     */
+    ExperimentalFeatureSettings mockXpSettings;
+    mockXpSettings.set("experimental-features", "ca-derivations");
+
+    auto * v = state.allocValue();
+    state.mkOutputString(*v, b, std::nullopt, mockXpSettings);
+    auto [d, _] = state.coerceToSingleDerivedPathUnchecked(noPos, *v, "");
+    RC_ASSERT(SingleDerivedPath { b } == d);
+}
+
+RC_GTEST_FIXTURE_PROP(
+    DerivedPathExpressionTest,
+    prop_derived_path_built_out_path_round_trip,
+    (const SingleDerivedPath::Built & b, const StorePath & outPath))
+{
+    auto * v = state.allocValue();
+    state.mkOutputString(*v, b, outPath);
+    auto [d, _] = state.coerceToSingleDerivedPathUnchecked(noPos, *v, "");
+    RC_ASSERT(SingleDerivedPath { b } == d);
+}
+
+#endif
+
+} /* namespace nix */

src/libexpr-tests/eval.cc

@@ -0,0 +1,141 @@
+#include <gmock/gmock.h>
+#include <gtest/gtest.h>
+
+#include "eval.hh"
+#include "tests/libexpr.hh"
+
+namespace nix {
+
+TEST(nix_isAllowedURI, http_example_com) {
+    Strings allowed;
+    allowed.push_back("http://example.com");
+
+    ASSERT_TRUE(isAllowedURI("http://example.com", allowed));
+    ASSERT_TRUE(isAllowedURI("http://example.com/foo", allowed));
+    ASSERT_TRUE(isAllowedURI("http://example.com/foo/", allowed));
+    ASSERT_FALSE(isAllowedURI("/", allowed));
+    ASSERT_FALSE(isAllowedURI("http://example.co", allowed));
+    ASSERT_FALSE(isAllowedURI("http://example.como", allowed));
+    ASSERT_FALSE(isAllowedURI("http://example.org", allowed));
+    ASSERT_FALSE(isAllowedURI("http://example.org/foo", allowed));
+}
+
+TEST(nix_isAllowedURI, http_example_com_foo) {
+    Strings allowed;
+    allowed.push_back("http://example.com/foo");
+
+    ASSERT_TRUE(isAllowedURI("http://example.com/foo", allowed));
+    ASSERT_TRUE(isAllowedURI("http://example.com/foo/", allowed));
+    ASSERT_FALSE(isAllowedURI("/foo", allowed));
+    ASSERT_FALSE(isAllowedURI("http://example.com", allowed));
+    ASSERT_FALSE(isAllowedURI("http://example.como", allowed));
+    ASSERT_FALSE(isAllowedURI("http://example.org/foo", allowed));
+    // Broken?
+    // ASSERT_TRUE(isAllowedURI("http://example.com/foo?ok=1", allowed));
+}
+
+TEST(nix_isAllowedURI, http) {
+    Strings allowed;
+    allowed.push_back("http://");
+
+    ASSERT_TRUE(isAllowedURI("http://", allowed));
+    ASSERT_TRUE(isAllowedURI("http://example.com", allowed));
+    ASSERT_TRUE(isAllowedURI("http://example.com/foo", allowed));
+    ASSERT_TRUE(isAllowedURI("http://example.com/foo/", allowed));
+    ASSERT_TRUE(isAllowedURI("http://example.com", allowed));
+    ASSERT_FALSE(isAllowedURI("/", allowed));
+    ASSERT_FALSE(isAllowedURI("https://", allowed));
+    ASSERT_FALSE(isAllowedURI("http:foo", allowed));
+}
+
+TEST(nix_isAllowedURI, https) {
+    Strings allowed;
+    allowed.push_back("https://");
+
+    ASSERT_TRUE(isAllowedURI("https://example.com", allowed));
+    ASSERT_TRUE(isAllowedURI("https://example.com/foo", allowed));
+    ASSERT_FALSE(isAllowedURI("http://example.com", allowed));
+    ASSERT_FALSE(isAllowedURI("http://example.com/https:", allowed));
+}
+
+TEST(nix_isAllowedURI, absolute_path) {
+    Strings allowed;
+    allowed.push_back("/var/evil"); // bad idea
+
+    ASSERT_TRUE(isAllowedURI("/var/evil", allowed));
+    ASSERT_TRUE(isAllowedURI("/var/evil/", allowed));
+    ASSERT_TRUE(isAllowedURI("/var/evil/foo", allowed));
+    ASSERT_TRUE(isAllowedURI("/var/evil/foo/", allowed));
+    ASSERT_FALSE(isAllowedURI("/", allowed));
+    ASSERT_FALSE(isAllowedURI("/var/evi", allowed));
+    ASSERT_FALSE(isAllowedURI("/var/evilo", allowed));
+    ASSERT_FALSE(isAllowedURI("/var/evilo/", allowed));
+    ASSERT_FALSE(isAllowedURI("/var/evilo/foo", allowed));
+    ASSERT_FALSE(isAllowedURI("http://example.com/var/evil", allowed));
+    ASSERT_FALSE(isAllowedURI("http://example.com//var/evil", allowed));
+    ASSERT_FALSE(isAllowedURI("http://example.com//var/evil/foo", allowed));
+}
+
+TEST(nix_isAllowedURI, file_url) {
+    Strings allowed;
+    allowed.push_back("file:///var/evil"); // bad idea
+
+    ASSERT_TRUE(isAllowedURI("file:///var/evil", allowed));
+    ASSERT_TRUE(isAllowedURI("file:///var/evil/", allowed));
+    ASSERT_TRUE(isAllowedURI("file:///var/evil/foo", allowed));
+    ASSERT_TRUE(isAllowedURI("file:///var/evil/foo/", allowed));
+    ASSERT_FALSE(isAllowedURI("/", allowed));
+    ASSERT_FALSE(isAllowedURI("/var/evi", allowed));
+    ASSERT_FALSE(isAllowedURI("/var/evilo", allowed));
+    ASSERT_FALSE(isAllowedURI("/var/evilo/", allowed));
+    ASSERT_FALSE(isAllowedURI("/var/evilo/foo", allowed));
+    ASSERT_FALSE(isAllowedURI("http://example.com/var/evil", allowed));
+    ASSERT_FALSE(isAllowedURI("http://example.com//var/evil", allowed));
+    ASSERT_FALSE(isAllowedURI("http://example.com//var/evil/foo", allowed));
+    ASSERT_FALSE(isAllowedURI("http://var/evil", allowed));
+    ASSERT_FALSE(isAllowedURI("http:///var/evil", allowed));
+    ASSERT_FALSE(isAllowedURI("http://var/evil/", allowed));
+    ASSERT_FALSE(isAllowedURI("file:///var/evi", allowed));
+    ASSERT_FALSE(isAllowedURI("file:///var/evilo", allowed));
+    ASSERT_FALSE(isAllowedURI("file:///var/evilo/", allowed));
+    ASSERT_FALSE(isAllowedURI("file:///var/evilo/foo", allowed));
+    ASSERT_FALSE(isAllowedURI("file:///", allowed));
+    ASSERT_FALSE(isAllowedURI("file://", allowed));
+}
+
+TEST(nix_isAllowedURI, github_all) {
+    Strings allowed;
+    allowed.push_back("github:");
+    ASSERT_TRUE(isAllowedURI("github:", allowed));
+    ASSERT_TRUE(isAllowedURI("github:foo/bar", allowed));
+    ASSERT_TRUE(isAllowedURI("github:foo/bar/feat-multi-bar", allowed));
+    ASSERT_TRUE(isAllowedURI("github:foo/bar?ref=refs/heads/feat-multi-bar", allowed));
+    ASSERT_TRUE(isAllowedURI("github://foo/bar", allowed));
+    ASSERT_FALSE(isAllowedURI("https://github:443/foo/bar/archive/master.tar.gz", allowed));
+    ASSERT_FALSE(isAllowedURI("file://github:foo/bar/archive/master.tar.gz", allowed));
+    ASSERT_FALSE(isAllowedURI("file:///github:foo/bar/archive/master.tar.gz", allowed));
+    ASSERT_FALSE(isAllowedURI("github", allowed));
+}
+
+TEST(nix_isAllowedURI, github_org) {
+    Strings allowed;
+    allowed.push_back("github:foo");
+    ASSERT_FALSE(isAllowedURI("github:", allowed));
+    ASSERT_TRUE(isAllowedURI("github:foo/bar", allowed));
+    ASSERT_TRUE(isAllowedURI("github:foo/bar/feat-multi-bar", allowed));
+    ASSERT_TRUE(isAllowedURI("github:foo/bar?ref=refs/heads/feat-multi-bar", allowed));
+    ASSERT_FALSE(isAllowedURI("github://foo/bar", allowed));
+    ASSERT_FALSE(isAllowedURI("https://github:443/foo/bar/archive/master.tar.gz", allowed));
+    ASSERT_FALSE(isAllowedURI("file://github:foo/bar/archive/master.tar.gz", allowed));
+    ASSERT_FALSE(isAllowedURI("file:///github:foo/bar/archive/master.tar.gz", allowed));
+}
+
+TEST(nix_isAllowedURI, non_scheme_colon) {
+    Strings allowed;
+    allowed.push_back("https://foo/bar:");
+    ASSERT_TRUE(isAllowedURI("https://foo/bar:", allowed));
+    ASSERT_TRUE(isAllowedURI("https://foo/bar:/baz", allowed));
+    ASSERT_FALSE(isAllowedURI("https://foo/bar:baz", allowed));
+}
+
+} // namespace nix

src/libexpr-tests/json.cc

@@ -0,0 +1,68 @@
+#include "tests/libexpr.hh"
+#include "value-to-json.hh"
+
+namespace nix {
+// Testing the conversion to JSON
+
+    class JSONValueTest : public LibExprTest {
+        protected:
+            std::string getJSONValue(Value& value) {
+                std::stringstream ss;
+                NixStringContext ps;
+                printValueAsJSON(state, true, value, noPos, ss, ps);
+                return ss.str();
+            }
+    };
+
+    TEST_F(JSONValueTest, null) {
+        Value v;
+        v.mkNull();
+        ASSERT_EQ(getJSONValue(v), "null");
+    }
+
+    TEST_F(JSONValueTest, BoolFalse) {
+        Value v;
+        v.mkBool(false);
+        ASSERT_EQ(getJSONValue(v),"false");
+    }
+
+    TEST_F(JSONValueTest, BoolTrue) {
+        Value v;
+        v.mkBool(true);
+        ASSERT_EQ(getJSONValue(v), "true");
+    }
+
+    TEST_F(JSONValueTest, IntPositive) {
+        Value v;
+        v.mkInt(100);
+        ASSERT_EQ(getJSONValue(v), "100");
+    }
+
+    TEST_F(JSONValueTest, IntNegative) {
+        Value v;
+        v.mkInt(-100);
+        ASSERT_EQ(getJSONValue(v), "-100");
+    }
+
+    TEST_F(JSONValueTest, String) {
+        Value v;
+        v.mkString("test");
+        ASSERT_EQ(getJSONValue(v), "\"test\"");
+    }
+
+    TEST_F(JSONValueTest, StringQuotes) {
+        Value v;
+
+        v.mkString("test\"");
+        ASSERT_EQ(getJSONValue(v), "\"test\\\"\"");
+    }
+
+    // The dummy store doesn't support writing files. Fails with this exception message:
+    // C++ exception with description "error: operation 'addToStoreFromDump' is
+    // not supported by store 'dummy'" thrown in the test body.
+    TEST_F(JSONValueTest, DISABLED_Path) {
+        Value v;
+        v.mkPath(state.rootPath(CanonPath("/test")));
+        ASSERT_EQ(getJSONValue(v), "\"/nix/store/g1w7hy3qg1w7hy3qg1w7hy3qg1w7hy3q-x\"");
+    }
+} /* namespace nix */

src/libexpr-tests/local.mk

@@ -0,0 +1,45 @@
+check: libexpr-tests_RUN
+
+programs += libexpr-tests
+
+libexpr-tests_NAME := libnixexpr-tests
+
+libexpr-tests_ENV := _NIX_TEST_UNIT_DATA=$(d)/data GTEST_OUTPUT=xml:$$testresults/libexpr-tests.xml
+
+libexpr-tests_DIR := $(d)
+
+ifeq ($(INSTALL_UNIT_TESTS), yes)
+  libexpr-tests_INSTALL_DIR := $(checkbindir)
+else
+  libexpr-tests_INSTALL_DIR :=
+endif
+
+libexpr-tests_SOURCES := \
+    $(wildcard $(d)/*.cc) \
+    $(wildcard $(d)/value/*.cc) \
+    $(wildcard $(d)/flake/*.cc)
+
+libexpr-tests_EXTRA_INCLUDES = \
+    -I src/libexpr-test-support \
+    -I src/libstore-test-support \
+    -I src/libutil-test-support \
+    $(INCLUDE_libexpr) \
+    $(INCLUDE_libexprc) \
+    $(INCLUDE_libfetchers) \
+    $(INCLUDE_libstore) \
+    $(INCLUDE_libstorec) \
+    $(INCLUDE_libutil) \
+    $(INCLUDE_libutilc)
+
+libexpr-tests_CXXFLAGS += $(libexpr-tests_EXTRA_INCLUDES)
+
+libexpr-tests_LIBS = \
+    libexpr-test-support libstore-test-support libutil-test-support \
+    libexpr libexprc libfetchers libstore libstorec libutil libutilc
+
+libexpr-tests_LDFLAGS := -lrapidcheck $(GTEST_LIBS) -lgmock
+
+ifdef HOST_WINDOWS
+  # Increase the default reserved stack size to 65 MB so Nix doesn't run out of space
+  libexpr-tests_LDFLAGS += -Wl,--stack,$(shell echo $$((65 * 1024 * 1024)))
+endif

src/libexpr-tests/main.cc

@@ -0,0 +1,42 @@
+#include <gtest/gtest.h>
+#include <cstdlib>
+#include "globals.hh"
+#include "logging.hh"
+
+using namespace nix;
+
+int main (int argc, char **argv) {
+    if (argc > 1 && std::string_view(argv[1]) == "__build-remote") {
+        printError("test-build-remote: not supported in libexpr unit tests");
+        return 1;
+    }
+
+    // Disable build hook. We won't be testing remote builds in these unit tests. If we do, fix the above build hook.
+    settings.buildHook = {};
+
+    #if __linux__ // should match the conditional around sandboxBuildDir declaration.
+
+    // When building and testing nix within the host's Nix sandbox, our store dir will be located in the host's sandboxBuildDir, e.g.:
+    // Host
+    //   storeDir = /nix/store
+    //   sandboxBuildDir = /build
+    // This process
+    //   storeDir = /build/foo/bar/store
+    //   sandboxBuildDir = /build
+    // However, we have a rule that the store dir must not be inside the storeDir, so we need to pick a different sandboxBuildDir.
+    settings.sandboxBuildDir = "/test-build-dir-instead-of-usual-build-dir";
+    #endif
+
+    #if __APPLE__
+    // Avoid this error, when already running in a sandbox:
+    // sandbox-exec: sandbox_apply: Operation not permitted
+    settings.sandboxMode = smDisabled;
+    setEnv("_NIX_TEST_NO_SANDBOX", "1");
+    #endif
+
+    // For pipe operator tests in trivial.cc
+    experimentalFeatureSettings.set("experimental-features", "pipe-operators");
+
+    ::testing::InitGoogleTest(&argc, argv);
+    return RUN_ALL_TESTS();
+}

src/libexpr-tests/meson.build

@@ -0,0 +1,92 @@
+project('nix-expr-tests', 'cpp',
+  version : files('.version'),
+  default_options : [
+    'cpp_std=c++2a',
+    # TODO(Qyriad): increase the warning level
+    'warning_level=1',
+    'debug=true',
+    'optimization=2',
+    'errorlogs=true', # Please print logs for tests that fail
+  ],
+  meson_version : '>= 1.1',
+  license : 'LGPL-2.1-or-later',
+)
+
+cxx = meson.get_compiler('cpp')
+
+subdir('build-utils-meson/deps-lists')
+
+deps_private_maybe_subproject = [
+  dependency('nix-expr'),
+  dependency('nix-expr-c'),
+  dependency('nix-expr-test-support'),
+]
+deps_public_maybe_subproject = [
+]
+subdir('build-utils-meson/subprojects')
+
+subdir('build-utils-meson/threads')
+
+subdir('build-utils-meson/export-all-symbols')
+
+rapidcheck = dependency('rapidcheck')
+deps_private += rapidcheck
+
+gtest = dependency('gtest')
+deps_private += gtest
+
+gtest = dependency('gmock')
+deps_private += gtest
+
+add_project_arguments(
+  # TODO(Qyriad): Yes this is how the autoconf+Make system did it.
+  # It would be nice for our headers to be idempotent instead.
+  '-include', 'config-util.hh',
+  '-include', 'config-store.hh',
+  '-include', 'config-expr.hh',
+  '-include', 'config-util.h',
+  '-include', 'config-store.h',
+  '-include', 'config-expr.h',
+  language : 'cpp',
+)
+
+subdir('build-utils-meson/diagnostics')
+
+sources = files(
+  'derived-path.cc',
+  'error_traces.cc',
+  'eval.cc',
+  'json.cc',
+  'main.cc',
+  'nix_api_expr.cc',
+  'nix_api_external.cc',
+  'nix_api_value.cc',
+  'primops.cc',
+  'search-path.cc',
+  'trivial.cc',
+  'value/context.cc',
+  'value/print.cc',
+  'value/value.cc',
+)
+
+include_dirs = [include_directories('.')]
+
+
+this_exe = executable(
+  meson.project_name(),
+  sources,
+  dependencies : deps_private_subproject + deps_private + deps_other,
+  include_directories : include_dirs,
+  # TODO: -lrapidcheck, see ../libutil-support/build.meson
+  link_args: linker_export_flags + ['-lrapidcheck'],
+  install : true,
+)
+
+test(
+  meson.project_name(),
+  this_exe,
+  env : {
+    '_NIX_TEST_UNIT_DATA': meson.current_source_dir() / 'data',
+  },
+  protocol : 'gtest',
+)

src/libexpr-tests/nix_api_expr.cc

@@ -0,0 +1,404 @@
+#include "nix_api_store.h"
+#include "nix_api_store_internal.h"
+#include "nix_api_util.h"
+#include "nix_api_util_internal.h"
+#include "nix_api_expr.h"
+#include "nix_api_value.h"
+
+#include "tests/nix_api_expr.hh"
+#include "tests/string_callback.hh"
+
+#include <gmock/gmock.h>
+#include <gtest/gtest.h>
+
+namespace nixC {
+
+TEST_F(nix_api_expr_test, nix_expr_eval_from_string)
+{
+    nix_expr_eval_from_string(nullptr, state, "builtins.nixVersion", ".", value);
+    nix_value_force(nullptr, state, value);
+    std::string result;
+    nix_get_string(nullptr, value, OBSERVE_STRING(result));
+
+    ASSERT_STREQ(PACKAGE_VERSION, result.c_str());
+}
+
+TEST_F(nix_api_expr_test, nix_expr_eval_add_numbers)
+{
+    nix_expr_eval_from_string(nullptr, state, "1 + 1", ".", value);
+    nix_value_force(nullptr, state, value);
+    auto result = nix_get_int(nullptr, value);
+
+    ASSERT_EQ(2, result);
+}
+
+TEST_F(nix_api_expr_test, nix_expr_eval_drv)
+{
+    auto expr = R"(derivation { name = "myname"; builder = "mybuilder"; system = "mysystem"; })";
+    nix_expr_eval_from_string(nullptr, state, expr, ".", value);
+    ASSERT_EQ(NIX_TYPE_ATTRS, nix_get_type(nullptr, value));
+
+    EvalState * stateFn = nix_state_create(nullptr, nullptr, store);
+    nix_value * valueFn = nix_alloc_value(nullptr, state);
+    nix_expr_eval_from_string(nullptr, stateFn, "builtins.toString", ".", valueFn);
+    ASSERT_EQ(NIX_TYPE_FUNCTION, nix_get_type(nullptr, valueFn));
+
+    EvalState * stateResult = nix_state_create(nullptr, nullptr, store);
+    nix_value * valueResult = nix_alloc_value(nullptr, stateResult);
+    nix_value_call(ctx, stateResult, valueFn, value, valueResult);
+    ASSERT_EQ(NIX_TYPE_STRING, nix_get_type(nullptr, valueResult));
+
+    std::string p;
+    nix_get_string(nullptr, valueResult, OBSERVE_STRING(p));
+    std::string pEnd = "-myname";
+    ASSERT_EQ(pEnd, p.substr(p.size() - pEnd.size()));
+
+    // Clean up
+    nix_gc_decref(nullptr, valueFn);
+    nix_state_free(stateFn);
+
+    nix_gc_decref(nullptr, valueResult);
+    nix_state_free(stateResult);
+}
+
+TEST_F(nix_api_expr_test, nix_build_drv)
+{
+    auto expr = R"(derivation { name = "myname";
+                                system = builtins.currentSystem;
+                                builder = "/bin/sh";
+                                args = [ "-c" "echo foo > $out" ];
+                              })";
+    nix_expr_eval_from_string(nullptr, state, expr, ".", value);
+
+    nix_value * drvPathValue = nix_get_attr_byname(nullptr, value, state, "drvPath");
+    std::string drvPath;
+    nix_get_string(nullptr, drvPathValue, OBSERVE_STRING(drvPath));
+
+    std::string p = drvPath;
+    std::string pEnd = "-myname.drv";
+    ASSERT_EQ(pEnd, p.substr(p.size() - pEnd.size()));
+
+    // NOTE: .drvPath should be usually be ignored. Output paths are more versatile.
+    //       See https://github.com/NixOS/nix/issues/6507
+    //       Use e.g. nix_string_realise to realise the output.
+    StorePath * drvStorePath = nix_store_parse_path(ctx, store, drvPath.c_str());
+    ASSERT_EQ(true, nix_store_is_valid_path(ctx, store, drvStorePath));
+
+    nix_value * outPathValue = nix_get_attr_byname(ctx, value, state, "outPath");
+    std::string outPath;
+    nix_get_string(ctx, outPathValue, OBSERVE_STRING(outPath));
+
+    p = outPath;
+    pEnd = "-myname";
+    ASSERT_EQ(pEnd, p.substr(p.size() - pEnd.size()));
+    ASSERT_EQ(true, drvStorePath->path.isDerivation());
+
+    StorePath * outStorePath = nix_store_parse_path(ctx, store, outPath.c_str());
+    ASSERT_EQ(false, nix_store_is_valid_path(ctx, store, outStorePath));
+
+    nix_store_realise(ctx, store, drvStorePath, nullptr, nullptr);
+    auto is_valid_path = nix_store_is_valid_path(ctx, store, outStorePath);
+    ASSERT_EQ(true, is_valid_path);
+
+    // Clean up
+    nix_store_path_free(drvStorePath);
+    nix_store_path_free(outStorePath);
+}
+
+TEST_F(nix_api_expr_test, nix_expr_realise_context_bad_value)
+{
+    auto expr = "true";
+    nix_expr_eval_from_string(ctx, state, expr, ".", value);
+    assert_ctx_ok();
+    auto r = nix_string_realise(ctx, state, value, false);
+    ASSERT_EQ(nullptr, r);
+    ASSERT_EQ(ctx->last_err_code, NIX_ERR_NIX_ERROR);
+    ASSERT_THAT(ctx->last_err, testing::Optional(testing::HasSubstr("cannot coerce")));
+}
+
+TEST_F(nix_api_expr_test, nix_expr_realise_context_bad_build)
+{
+    auto expr = R"(
+        derivation { name = "letsbuild";
+            system = builtins.currentSystem;
+            builder = "/bin/sh";
+            args = [ "-c" "echo failing a build for testing purposes; exit 1;" ];
+            }
+        )";
+    nix_expr_eval_from_string(ctx, state, expr, ".", value);
+    assert_ctx_ok();
+    auto r = nix_string_realise(ctx, state, value, false);
+    ASSERT_EQ(nullptr, r);
+    ASSERT_EQ(ctx->last_err_code, NIX_ERR_NIX_ERROR);
+    ASSERT_THAT(ctx->last_err, testing::Optional(testing::HasSubstr("failed with exit code 1")));
+}
+
+TEST_F(nix_api_expr_test, nix_expr_realise_context)
+{
+    // TODO (ca-derivations): add a content-addressed derivation output, which produces a placeholder
+    auto expr = R"(
+        ''
+            a derivation output: ${
+                derivation { name = "letsbuild";
+                    system = builtins.currentSystem;
+                    builder = "/bin/sh";
+                    args = [ "-c" "echo foo > $out" ];
+                    }}
+            a path: ${builtins.toFile "just-a-file" "ooh file good"}
+            a derivation path by itself: ${
+                builtins.unsafeDiscardOutputDependency
+                    (derivation {
+                        name = "not-actually-built-yet";
+                        system = builtins.currentSystem;
+                        builder = "/bin/sh";
+                        args = [ "-c" "echo foo > $out" ];
+                    }).drvPath}
+        ''
+        )";
+    nix_expr_eval_from_string(ctx, state, expr, ".", value);
+    assert_ctx_ok();
+    auto r = nix_string_realise(ctx, state, value, false);
+    assert_ctx_ok();
+    ASSERT_NE(nullptr, r);
+
+    auto s = std::string(nix_realised_string_get_buffer_start(r), nix_realised_string_get_buffer_size(r));
+
+    EXPECT_THAT(s, testing::StartsWith("a derivation output:"));
+    EXPECT_THAT(s, testing::HasSubstr("-letsbuild\n"));
+    EXPECT_THAT(s, testing::Not(testing::HasSubstr("-letsbuild.drv")));
+    EXPECT_THAT(s, testing::HasSubstr("a path:"));
+    EXPECT_THAT(s, testing::HasSubstr("-just-a-file"));
+    EXPECT_THAT(s, testing::Not(testing::HasSubstr("-just-a-file.drv")));
+    EXPECT_THAT(s, testing::Not(testing::HasSubstr("ooh file good")));
+    EXPECT_THAT(s, testing::HasSubstr("a derivation path by itself:"));
+    EXPECT_THAT(s, testing::EndsWith("-not-actually-built-yet.drv\n"));
+
+    std::vector<std::string> names;
+    size_t n = nix_realised_string_get_store_path_count(r);
+    for (size_t i = 0; i < n; ++i) {
+        const StorePath * p = nix_realised_string_get_store_path(r, i);
+        ASSERT_NE(nullptr, p);
+        std::string name;
+        nix_store_path_name(p, OBSERVE_STRING(name));
+        names.push_back(name);
+    }
+    std::sort(names.begin(), names.end());
+    ASSERT_EQ(3, names.size());
+    EXPECT_THAT(names[0], testing::StrEq("just-a-file"));
+    EXPECT_THAT(names[1], testing::StrEq("letsbuild"));
+    EXPECT_THAT(names[2], testing::StrEq("not-actually-built-yet.drv"));
+
+    nix_realised_string_free(r);
+}
+
+const char * SAMPLE_USER_DATA = "whatever";
+
+static void
+primop_square(void * user_data, nix_c_context * context, EvalState * state, nix_value ** args, nix_value * ret)
+{
+    assert(context);
+    assert(state);
+    assert(user_data == SAMPLE_USER_DATA);
+    auto i = nix_get_int(context, args[0]);
+    nix_init_int(context, ret, i * i);
+}
+
+TEST_F(nix_api_expr_test, nix_expr_primop)
+{
+    PrimOp * primop =
+        nix_alloc_primop(ctx, primop_square, 1, "square", nullptr, "square an integer", (void *) SAMPLE_USER_DATA);
+    assert_ctx_ok();
+    nix_value * primopValue = nix_alloc_value(ctx, state);
+    assert_ctx_ok();
+    nix_init_primop(ctx, primopValue, primop);
+    assert_ctx_ok();
+
+    nix_value * three = nix_alloc_value(ctx, state);
+    assert_ctx_ok();
+    nix_init_int(ctx, three, 3);
+    assert_ctx_ok();
+
+    nix_value * result = nix_alloc_value(ctx, state);
+    assert_ctx_ok();
+    nix_value_call(ctx, state, primopValue, three, result);
+    assert_ctx_ok();
+
+    auto r = nix_get_int(ctx, result);
+    ASSERT_EQ(9, r);
+}
+
+static void
+primop_repeat(void * user_data, nix_c_context * context, EvalState * state, nix_value ** args, nix_value * ret)
+{
+    assert(context);
+    assert(state);
+    assert(user_data == SAMPLE_USER_DATA);
+
+    // Get the string to repeat
+    std::string s;
+    if (nix_get_string(context, args[0], OBSERVE_STRING(s)) != NIX_OK)
+        return;
+
+    // Get the number of times to repeat
+    auto n = nix_get_int(context, args[1]);
+    if (nix_err_code(context) != NIX_OK)
+        return;
+
+    // Repeat the string
+    std::string result;
+    for (int i = 0; i < n; ++i)
+        result += s;
+
+    nix_init_string(context, ret, result.c_str());
+}
+
+TEST_F(nix_api_expr_test, nix_expr_primop_arity_2_multiple_calls)
+{
+    PrimOp * primop =
+        nix_alloc_primop(ctx, primop_repeat, 2, "repeat", nullptr, "repeat a string", (void *) SAMPLE_USER_DATA);
+    assert_ctx_ok();
+    nix_value * primopValue = nix_alloc_value(ctx, state);
+    assert_ctx_ok();
+    nix_init_primop(ctx, primopValue, primop);
+    assert_ctx_ok();
+
+    nix_value * hello = nix_alloc_value(ctx, state);
+    assert_ctx_ok();
+    nix_init_string(ctx, hello, "hello");
+    assert_ctx_ok();
+
+    nix_value * three = nix_alloc_value(ctx, state);
+    assert_ctx_ok();
+    nix_init_int(ctx, three, 3);
+    assert_ctx_ok();
+
+    nix_value * partial = nix_alloc_value(ctx, state);
+    assert_ctx_ok();
+    nix_value_call(ctx, state, primopValue, hello, partial);
+    assert_ctx_ok();
+
+    nix_value * result = nix_alloc_value(ctx, state);
+    assert_ctx_ok();
+    nix_value_call(ctx, state, partial, three, result);
+    assert_ctx_ok();
+
+    std::string r;
+    nix_get_string(ctx, result, OBSERVE_STRING(r));
+    ASSERT_STREQ("hellohellohello", r.c_str());
+}
+
+TEST_F(nix_api_expr_test, nix_expr_primop_arity_2_single_call)
+{
+    PrimOp * primop =
+        nix_alloc_primop(ctx, primop_repeat, 2, "repeat", nullptr, "repeat a string", (void *) SAMPLE_USER_DATA);
+    assert_ctx_ok();
+    nix_value * primopValue = nix_alloc_value(ctx, state);
+    assert_ctx_ok();
+    nix_init_primop(ctx, primopValue, primop);
+    assert_ctx_ok();
+
+    nix_value * hello = nix_alloc_value(ctx, state);
+    assert_ctx_ok();
+    nix_init_string(ctx, hello, "hello");
+    assert_ctx_ok();
+
+    nix_value * three = nix_alloc_value(ctx, state);
+    assert_ctx_ok();
+    nix_init_int(ctx, three, 3);
+    assert_ctx_ok();
+
+    nix_value * result = nix_alloc_value(ctx, state);
+    assert_ctx_ok();
+    NIX_VALUE_CALL(ctx, state, result, primopValue, hello, three);
+    assert_ctx_ok();
+
+    std::string r;
+    nix_get_string(ctx, result, OBSERVE_STRING(r));
+    assert_ctx_ok();
+
+    ASSERT_STREQ("hellohellohello", r.c_str());
+}
+
+static void
+primop_bad_no_return(void * user_data, nix_c_context * context, EvalState * state, nix_value ** args, nix_value * ret)
+{
+}
+
+TEST_F(nix_api_expr_test, nix_expr_primop_bad_no_return)
+{
+    PrimOp * primop =
+        nix_alloc_primop(ctx, primop_bad_no_return, 1, "badNoReturn", nullptr, "a broken primop", nullptr);
+    assert_ctx_ok();
+    nix_value * primopValue = nix_alloc_value(ctx, state);
+    assert_ctx_ok();
+    nix_init_primop(ctx, primopValue, primop);
+    assert_ctx_ok();
+
+    nix_value * three = nix_alloc_value(ctx, state);
+    assert_ctx_ok();
+    nix_init_int(ctx, three, 3);
+    assert_ctx_ok();
+
+    nix_value * result = nix_alloc_value(ctx, state);
+    assert_ctx_ok();
+    nix_value_call(ctx, state, primopValue, three, result);
+    ASSERT_EQ(ctx->last_err_code, NIX_ERR_NIX_ERROR);
+    ASSERT_THAT(
+        ctx->last_err,
+        testing::Optional(
+            testing::HasSubstr("Implementation error in custom function: return value was not initialized")));
+    ASSERT_THAT(ctx->last_err, testing::Optional(testing::HasSubstr("badNoReturn")));
+}
+
+static void primop_bad_return_thunk(
+    void * user_data, nix_c_context * context, EvalState * state, nix_value ** args, nix_value * ret)
+{
+    nix_init_apply(context, ret, args[0], args[1]);
+}
+TEST_F(nix_api_expr_test, nix_expr_primop_bad_return_thunk)
+{
+    PrimOp * primop =
+        nix_alloc_primop(ctx, primop_bad_return_thunk, 2, "badReturnThunk", nullptr, "a broken primop", nullptr);
+    assert_ctx_ok();
+    nix_value * primopValue = nix_alloc_value(ctx, state);
+    assert_ctx_ok();
+    nix_init_primop(ctx, primopValue, primop);
+    assert_ctx_ok();
+
+    nix_value * toString = nix_alloc_value(ctx, state);
+    assert_ctx_ok();
+    nix_expr_eval_from_string(ctx, state, "builtins.toString", ".", toString);
+    assert_ctx_ok();
+
+    nix_value * four = nix_alloc_value(ctx, state);
+    assert_ctx_ok();
+    nix_init_int(ctx, four, 4);
+    assert_ctx_ok();
+
+    nix_value * result = nix_alloc_value(ctx, state);
+    assert_ctx_ok();
+    NIX_VALUE_CALL(ctx, state, result, primopValue, toString, four);
+
+    ASSERT_EQ(ctx->last_err_code, NIX_ERR_NIX_ERROR);
+    ASSERT_THAT(
+        ctx->last_err,
+        testing::Optional(
+            testing::HasSubstr("Implementation error in custom function: return value must not be a thunk")));
+    ASSERT_THAT(ctx->last_err, testing::Optional(testing::HasSubstr("badReturnThunk")));
+}
+
+TEST_F(nix_api_expr_test, nix_value_call_multi_no_args)
+{
+    nix_value * n = nix_alloc_value(ctx, state);
+    nix_init_int(ctx, n, 3);
+    assert_ctx_ok();
+
+    nix_value * r = nix_alloc_value(ctx, state);
+    nix_value_call_multi(ctx, state, n, 0, nullptr, r);
+    assert_ctx_ok();
+
+    auto rInt = nix_get_int(ctx, r);
+    assert_ctx_ok();
+    ASSERT_EQ(3, rInt);
+}
+} // namespace nixC

src/libexpr-tests/nix_api_external.cc

@@ -0,0 +1,68 @@
+#include "nix_api_store.h"
+#include "nix_api_store_internal.h"
+#include "nix_api_util.h"
+#include "nix_api_util_internal.h"
+#include "nix_api_expr.h"
+#include "nix_api_expr_internal.h"
+#include "nix_api_value.h"
+#include "nix_api_external.h"
+
+#include "tests/nix_api_expr.hh"
+#include "tests/string_callback.hh"
+
+#include <gtest/gtest.h>
+
+namespace nixC {
+
+class MyExternalValueDesc : public NixCExternalValueDesc
+{
+public:
+    MyExternalValueDesc(int x)
+        : _x(x)
+    {
+        print = print_function;
+        showType = show_type_function;
+        typeOf = type_of_function;
+    }
+
+private:
+    int _x;
+    static void print_function(void * self, nix_printer * printer) {}
+
+    static void show_type_function(void * self, nix_string_return * res) {}
+
+    static void type_of_function(void * self, nix_string_return * res)
+    {
+        MyExternalValueDesc * obj = static_cast<MyExternalValueDesc *>(self);
+
+        std::string type_string = "nix-external<MyExternalValueDesc( ";
+        type_string += std::to_string(obj->_x);
+        type_string += " )>";
+        res->str = &*type_string.begin();
+    }
+};
+
+TEST_F(nix_api_expr_test, nix_expr_eval_external)
+{
+    MyExternalValueDesc * external = new MyExternalValueDesc(42);
+    ExternalValue * val = nix_create_external_value(ctx, external, external);
+    nix_init_external(ctx, value, val);
+
+    EvalState * stateResult = nix_state_create(nullptr, nullptr, store);
+    nix_value * valueResult = nix_alloc_value(nullptr, stateResult);
+
+    EvalState * stateFn = nix_state_create(nullptr, nullptr, store);
+    nix_value * valueFn = nix_alloc_value(nullptr, stateFn);
+
+    nix_expr_eval_from_string(nullptr, state, "builtins.typeOf", ".", valueFn);
+
+    ASSERT_EQ(NIX_TYPE_EXTERNAL, nix_get_type(nullptr, value));
+
+    nix_value_call(ctx, state, valueFn, value, valueResult);
+
+    std::string string_value;
+    nix_get_string(nullptr, valueResult, OBSERVE_STRING(string_value));
+    ASSERT_STREQ("nix-external<MyExternalValueDesc( 42 )>", string_value.c_str());
+}
+
+}

src/libexpr-tests/nix_api_value.cc

@@ -0,0 +1,402 @@
+#include "nix_api_store.h"
+#include "nix_api_store_internal.h"
+#include "nix_api_util.h"
+#include "nix_api_util_internal.h"
+#include "nix_api_expr.h"
+#include "nix_api_value.h"
+#include "nix_api_expr_internal.h"
+
+#include "tests/nix_api_expr.hh"
+#include "tests/string_callback.hh"
+
+#include "gmock/gmock.h"
+#include <cstddef>
+#include <cstdlib>
+#include <gtest/gtest.h>
+
+namespace nixC {
+
+TEST_F(nix_api_expr_test, as_nix_value_ptr)
+{
+    // nix_alloc_value casts nix::Value to nix_value
+    // It should be obvious from the decl that that works, but if it doesn't,
+    // the whole implementation would be utterly broken.
+    ASSERT_EQ(sizeof(nix::Value), sizeof(nix_value));
+}
+
+TEST_F(nix_api_expr_test, nix_value_get_int_invalid)
+{
+    ASSERT_EQ(0, nix_get_int(ctx, nullptr));
+    assert_ctx_err();
+    ASSERT_EQ(0, nix_get_int(ctx, value));
+    assert_ctx_err();
+}
+
+TEST_F(nix_api_expr_test, nix_value_set_get_int)
+{
+    int myInt = 1;
+    nix_init_int(ctx, value, myInt);
+
+    ASSERT_EQ(myInt, nix_get_int(ctx, value));
+    ASSERT_STREQ("an integer", nix_get_typename(ctx, value));
+    ASSERT_EQ(NIX_TYPE_INT, nix_get_type(ctx, value));
+}
+
+TEST_F(nix_api_expr_test, nix_value_set_get_float_invalid)
+{
+    ASSERT_DOUBLE_EQ(0.0, nix_get_float(ctx, nullptr));
+    assert_ctx_err();
+    ASSERT_DOUBLE_EQ(0.0, nix_get_float(ctx, value));
+    assert_ctx_err();
+}
+
+TEST_F(nix_api_expr_test, nix_value_set_get_float)
+{
+    double myDouble = 1.0;
+    nix_init_float(ctx, value, myDouble);
+
+    ASSERT_DOUBLE_EQ(myDouble, nix_get_float(ctx, value));
+    ASSERT_STREQ("a float", nix_get_typename(ctx, value));
+    ASSERT_EQ(NIX_TYPE_FLOAT, nix_get_type(ctx, value));
+}
+
+TEST_F(nix_api_expr_test, nix_value_set_get_bool_invalid)
+{
+    ASSERT_EQ(false, nix_get_bool(ctx, nullptr));
+    assert_ctx_err();
+    ASSERT_EQ(false, nix_get_bool(ctx, value));
+    assert_ctx_err();
+}
+
+TEST_F(nix_api_expr_test, nix_value_set_get_bool)
+{
+    bool myBool = true;
+    nix_init_bool(ctx, value, myBool);
+
+    ASSERT_EQ(myBool, nix_get_bool(ctx, value));
+    ASSERT_STREQ("a Boolean", nix_get_typename(ctx, value));
+    ASSERT_EQ(NIX_TYPE_BOOL, nix_get_type(ctx, value));
+}
+
+TEST_F(nix_api_expr_test, nix_value_set_get_string_invalid)
+{
+    std::string string_value;
+    ASSERT_EQ(NIX_ERR_UNKNOWN, nix_get_string(ctx, nullptr, OBSERVE_STRING(string_value)));
+    assert_ctx_err();
+    ASSERT_EQ(NIX_ERR_UNKNOWN, nix_get_string(ctx, value, OBSERVE_STRING(string_value)));
+    assert_ctx_err();
+}
+
+TEST_F(nix_api_expr_test, nix_value_set_get_string)
+{
+    std::string string_value;
+    const char * myString = "some string";
+    nix_init_string(ctx, value, myString);
+
+    nix_get_string(ctx, value, OBSERVE_STRING(string_value));
+    ASSERT_STREQ(myString, string_value.c_str());
+    ASSERT_STREQ("a string", nix_get_typename(ctx, value));
+    ASSERT_EQ(NIX_TYPE_STRING, nix_get_type(ctx, value));
+}
+
+TEST_F(nix_api_expr_test, nix_value_set_get_null_invalid)
+{
+    ASSERT_EQ(NULL, nix_get_typename(ctx, value));
+    assert_ctx_err();
+}
+
+TEST_F(nix_api_expr_test, nix_value_set_get_null)
+{
+    nix_init_null(ctx, value);
+
+    ASSERT_STREQ("null", nix_get_typename(ctx, value));
+    ASSERT_EQ(NIX_TYPE_NULL, nix_get_type(ctx, value));
+}
+
+TEST_F(nix_api_expr_test, nix_value_set_get_path_invalid)
+{
+    ASSERT_EQ(nullptr, nix_get_path_string(ctx, nullptr));
+    assert_ctx_err();
+    ASSERT_EQ(nullptr, nix_get_path_string(ctx, value));
+    assert_ctx_err();
+}
+TEST_F(nix_api_expr_test, nix_value_set_get_path)
+{
+    const char * p = "/nix/store/40s0qmrfb45vlh6610rk29ym318dswdr-myname";
+    nix_init_path_string(ctx, state, value, p);
+
+    ASSERT_STREQ(p, nix_get_path_string(ctx, value));
+    ASSERT_STREQ("a path", nix_get_typename(ctx, value));
+    ASSERT_EQ(NIX_TYPE_PATH, nix_get_type(ctx, value));
+}
+
+TEST_F(nix_api_expr_test, nix_build_and_init_list_invalid)
+{
+    ASSERT_EQ(nullptr, nix_get_list_byidx(ctx, nullptr, state, 0));
+    assert_ctx_err();
+    ASSERT_EQ(0, nix_get_list_size(ctx, nullptr));
+    assert_ctx_err();
+
+    ASSERT_EQ(nullptr, nix_get_list_byidx(ctx, value, state, 0));
+    assert_ctx_err();
+    ASSERT_EQ(0, nix_get_list_size(ctx, value));
+    assert_ctx_err();
+}
+
+TEST_F(nix_api_expr_test, nix_build_and_init_list)
+{
+    int size = 10;
+    ListBuilder * builder = nix_make_list_builder(ctx, state, size);
+
+    nix_value * intValue = nix_alloc_value(ctx, state);
+    nix_value * intValue2 = nix_alloc_value(ctx, state);
+
+    // `init` and `insert` can be called in any order
+    nix_init_int(ctx, intValue, 42);
+    nix_list_builder_insert(ctx, builder, 0, intValue);
+    nix_list_builder_insert(ctx, builder, 1, intValue2);
+    nix_init_int(ctx, intValue2, 43);
+
+    nix_make_list(ctx, builder, value);
+    nix_list_builder_free(builder);
+
+    ASSERT_EQ(42, nix_get_int(ctx, nix_get_list_byidx(ctx, value, state, 0)));
+    ASSERT_EQ(43, nix_get_int(ctx, nix_get_list_byidx(ctx, value, state, 1)));
+    ASSERT_EQ(nullptr, nix_get_list_byidx(ctx, value, state, 2));
+    ASSERT_EQ(10, nix_get_list_size(ctx, value));
+
+    ASSERT_STREQ("a list", nix_get_typename(ctx, value));
+    ASSERT_EQ(NIX_TYPE_LIST, nix_get_type(ctx, value));
+
+    // Clean up
+    nix_gc_decref(ctx, intValue);
+}
+
+TEST_F(nix_api_expr_test, nix_build_and_init_attr_invalid)
+{
+    ASSERT_EQ(nullptr, nix_get_attr_byname(ctx, nullptr, state, 0));
+    assert_ctx_err();
+    ASSERT_EQ(nullptr, nix_get_attr_byidx(ctx, nullptr, state, 0, nullptr));
+    assert_ctx_err();
+    ASSERT_EQ(nullptr, nix_get_attr_name_byidx(ctx, nullptr, state, 0));
+    assert_ctx_err();
+    ASSERT_EQ(0, nix_get_attrs_size(ctx, nullptr));
+    assert_ctx_err();
+    ASSERT_EQ(false, nix_has_attr_byname(ctx, nullptr, state, "no-value"));
+    assert_ctx_err();
+
+    ASSERT_EQ(nullptr, nix_get_attr_byname(ctx, value, state, 0));
+    assert_ctx_err();
+    ASSERT_EQ(nullptr, nix_get_attr_byidx(ctx, value, state, 0, nullptr));
+    assert_ctx_err();
+    ASSERT_EQ(nullptr, nix_get_attr_name_byidx(ctx, value, state, 0));
+    assert_ctx_err();
+    ASSERT_EQ(0, nix_get_attrs_size(ctx, value));
+    assert_ctx_err();
+    ASSERT_EQ(false, nix_has_attr_byname(ctx, value, state, "no-value"));
+    assert_ctx_err();
+}
+
+TEST_F(nix_api_expr_test, nix_build_and_init_attr)
+{
+    int size = 10;
+    const char ** out_name = (const char **) malloc(sizeof(char *));
+
+    BindingsBuilder * builder = nix_make_bindings_builder(ctx, state, size);
+
+    nix_value * intValue = nix_alloc_value(ctx, state);
+    nix_init_int(ctx, intValue, 42);
+
+    nix_value * stringValue = nix_alloc_value(ctx, state);
+    nix_init_string(ctx, stringValue, "foo");
+
+    nix_bindings_builder_insert(ctx, builder, "a", intValue);
+    nix_bindings_builder_insert(ctx, builder, "b", stringValue);
+    nix_make_attrs(ctx, value, builder);
+    nix_bindings_builder_free(builder);
+
+    ASSERT_EQ(2, nix_get_attrs_size(ctx, value));
+
+    nix_value * out_value = nix_get_attr_byname(ctx, value, state, "a");
+    ASSERT_EQ(42, nix_get_int(ctx, out_value));
+    nix_gc_decref(ctx, out_value);
+
+    out_value = nix_get_attr_byidx(ctx, value, state, 0, out_name);
+    ASSERT_EQ(42, nix_get_int(ctx, out_value));
+    ASSERT_STREQ("a", *out_name);
+    nix_gc_decref(ctx, out_value);
+
+    ASSERT_STREQ("a", nix_get_attr_name_byidx(ctx, value, state, 0));
+
+    ASSERT_EQ(true, nix_has_attr_byname(ctx, value, state, "b"));
+    ASSERT_EQ(false, nix_has_attr_byname(ctx, value, state, "no-value"));
+
+    out_value = nix_get_attr_byname(ctx, value, state, "b");
+    std::string string_value;
+    nix_get_string(ctx, out_value, OBSERVE_STRING(string_value));
+    ASSERT_STREQ("foo", string_value.c_str());
+    nix_gc_decref(nullptr, out_value);
+
+    out_value = nix_get_attr_byidx(ctx, value, state, 1, out_name);
+    nix_get_string(ctx, out_value, OBSERVE_STRING(string_value));
+    ASSERT_STREQ("foo", string_value.c_str());
+    ASSERT_STREQ("b", *out_name);
+    nix_gc_decref(nullptr, out_value);
+
+    ASSERT_STREQ("b", nix_get_attr_name_byidx(ctx, value, state, 1));
+
+    ASSERT_STREQ("a set", nix_get_typename(ctx, value));
+    ASSERT_EQ(NIX_TYPE_ATTRS, nix_get_type(ctx, value));
+
+    // Clean up
+    nix_gc_decref(ctx, intValue);
+    nix_gc_decref(ctx, stringValue);
+    free(out_name);
+}
+
+TEST_F(nix_api_expr_test, nix_value_init)
+{
+    // Setup
+
+    // two = 2;
+    // f = a: a * a;
+
+    nix_value * two = nix_alloc_value(ctx, state);
+    nix_init_int(ctx, two, 2);
+
+    nix_value * f = nix_alloc_value(ctx, state);
+    nix_expr_eval_from_string(
+        ctx,
+        state,
+        R"(
+        a: a * a
+    )",
+        "<test>",
+        f);
+
+    // Test
+
+    // r = f two;
+
+    nix_value * r = nix_alloc_value(ctx, state);
+    nix_init_apply(ctx, r, f, two);
+    assert_ctx_ok();
+
+    ValueType t = nix_get_type(ctx, r);
+    assert_ctx_ok();
+
+    ASSERT_EQ(t, NIX_TYPE_THUNK);
+
+    nix_value_force(ctx, state, r);
+
+    t = nix_get_type(ctx, r);
+    assert_ctx_ok();
+
+    ASSERT_EQ(t, NIX_TYPE_INT);
+
+    int n = nix_get_int(ctx, r);
+    assert_ctx_ok();
+
+    ASSERT_EQ(n, 4);
+
+    // Clean up
+    nix_gc_decref(ctx, two);
+    nix_gc_decref(ctx, f);
+    nix_gc_decref(ctx, r);
+}
+
+TEST_F(nix_api_expr_test, nix_value_init_apply_error)
+{
+    nix_value * some_string = nix_alloc_value(ctx, state);
+    nix_init_string(ctx, some_string, "some string");
+    assert_ctx_ok();
+
+    nix_value * v = nix_alloc_value(ctx, state);
+    nix_init_apply(ctx, v, some_string, some_string);
+    assert_ctx_ok();
+
+    // All ok. Call has not been evaluated yet.
+
+    // Evaluate it
+    nix_value_force(ctx, state, v);
+    ASSERT_EQ(ctx->last_err_code, NIX_ERR_NIX_ERROR);
+    ASSERT_THAT(ctx->last_err.value(), testing::HasSubstr("attempt to call something which is not a function but"));
+
+    // Clean up
+    nix_gc_decref(ctx, some_string);
+    nix_gc_decref(ctx, v);
+}
+
+TEST_F(nix_api_expr_test, nix_value_init_apply_lazy_arg)
+{
+    // f is a lazy function: it does not evaluate its argument before returning its return value
+    // g is a helper to produce e
+    // e is a thunk that throws an exception
+    //
+    // r = f e
+    // r should not throw an exception, because e is not evaluated
+
+    nix_value * f = nix_alloc_value(ctx, state);
+    nix_expr_eval_from_string(
+        ctx,
+        state,
+        R"(
+        a: { foo = a; }
+    )",
+        "<test>",
+        f);
+    assert_ctx_ok();
+
+    nix_value * e = nix_alloc_value(ctx, state);
+    {
+        nix_value * g = nix_alloc_value(ctx, state);
+        nix_expr_eval_from_string(
+            ctx,
+            state,
+            R"(
+            _ignore: throw "error message for test case nix_value_init_apply_lazy_arg"
+        )",
+            "<test>",
+            g);
+        assert_ctx_ok();
+
+        nix_init_apply(ctx, e, g, g);
+        assert_ctx_ok();
+        nix_gc_decref(ctx, g);
+    }
+
+    nix_value * r = nix_alloc_value(ctx, state);
+    nix_init_apply(ctx, r, f, e);
+    assert_ctx_ok();
+
+    nix_value_force(ctx, state, r);
+    assert_ctx_ok();
+
+    auto n = nix_get_attrs_size(ctx, r);
+    assert_ctx_ok();
+    ASSERT_EQ(1, n);
+
+    // nix_get_attr_byname isn't lazy (it could have been) so it will throw the exception
+    nix_value * foo = nix_get_attr_byname(ctx, r, state, "foo");
+    ASSERT_EQ(nullptr, foo);
+    ASSERT_THAT(ctx->last_err.value(), testing::HasSubstr("error message for test case nix_value_init_apply_lazy_arg"));
+
+    // Clean up
+    nix_gc_decref(ctx, f);
+    nix_gc_decref(ctx, e);
+}
+
+TEST_F(nix_api_expr_test, nix_copy_value)
+{
+    nix_value * source = nix_alloc_value(ctx, state);
+
+    nix_init_int(ctx, source, 42);
+    nix_copy_value(ctx, value, source);
+
+    ASSERT_EQ(42, nix_get_int(ctx, value));
+
+    // Clean up
+    nix_gc_decref(ctx, source);
+}
+
+}

src/libexpr-tests/package.nix

@@ -0,0 +1,83 @@
+{ lib
+, buildPackages
+, stdenv
+, mkMesonExecutable
+
+, nix-expr
+, nix-expr-c
+, nix-expr-test-support
+
+, rapidcheck
+, gtest
+, runCommand
+
+# Configuration Options
+
+, version
+, resolvePath
+}:
+
+let
+  inherit (lib) fileset;
+in
+
+mkMesonExecutable (finalAttrs: {
+  pname = "nix-expr-tests";
+  inherit version;
+
+  workDir = ./.;
+  fileset = fileset.unions [
+    ../../build-utils-meson
+    ./build-utils-meson
+    ../../.version
+    ./.version
+    ./meson.build
+    # ./meson.options
+    (fileset.fileFilter (file: file.hasExt "cc") ./.)
+    (fileset.fileFilter (file: file.hasExt "hh") ./.)
+  ];
+
+  buildInputs = [
+    nix-expr
+    nix-expr-c
+    nix-expr-test-support
+    rapidcheck
+    gtest
+  ];
+
+  preConfigure =
+    # "Inline" .version so it's not a symlink, and includes the suffix.
+    # Do the meson utils, without modification.
+    ''
+      chmod u+w ./.version
+      echo ${version} > ../../.version
+    '';
+
+  mesonFlags = [
+  ];
+
+  env = lib.optionalAttrs (stdenv.isLinux && !(stdenv.hostPlatform.isStatic && stdenv.system == "aarch64-linux")) {
+    LDFLAGS = "-fuse-ld=gold";
+  };
+
+  passthru = {
+    tests = {
+      run = runCommand "${finalAttrs.pname}-run" {
+        meta.broken = !stdenv.hostPlatform.emulatorAvailable buildPackages;
+      } (lib.optionalString stdenv.hostPlatform.isWindows ''
+        export HOME="$PWD/home-dir"
+        mkdir -p "$HOME"
+      '' + ''
+        export _NIX_TEST_UNIT_DATA=${resolvePath ./data}
+        ${stdenv.hostPlatform.emulator buildPackages} ${lib.getExe finalAttrs.finalPackage}
+        touch $out
+      '');
+    };
+  };
+
+  meta = {
+    platforms = lib.platforms.unix ++ lib.platforms.windows;
+    mainProgram = finalAttrs.pname + stdenv.hostPlatform.extensions.executable;
+  };
+
+})

src/libexpr-tests/primops.cc

@@ -0,0 +1,860 @@
+#include <gmock/gmock.h>
+#include <gtest/gtest.h>
+
+#include "eval-settings.hh"
+#include "memory-source-accessor.hh"
+
+#include "tests/libexpr.hh"
+
+namespace nix {
+    class CaptureLogger : public Logger
+    {
+        std::ostringstream oss;
+
+        public:
+            CaptureLogger() {}
+
+            std::string get() const {
+                return oss.str();
+            }
+
+            void log(Verbosity lvl, std::string_view s) override {
+                oss << s << std::endl;
+            }
+
+            void logEI(const ErrorInfo & ei) override {
+                showErrorInfo(oss, ei, loggerSettings.showTrace.get());
+            }
+    };
+
+    class CaptureLogging {
+        Logger * oldLogger;
+        std::unique_ptr<CaptureLogger> tempLogger;
+        public:
+            CaptureLogging() : tempLogger(std::make_unique<CaptureLogger>()) {
+                oldLogger = logger;
+                logger = tempLogger.get();
+            }
+
+            ~CaptureLogging() {
+                logger = oldLogger;
+            }
+
+            std::string get() const {
+                return tempLogger->get();
+            }
+    };
+
+
+    // Testing eval of PrimOp's
+    class PrimOpTest : public LibExprTest {};
+
+
+    TEST_F(PrimOpTest, throw) {
+        ASSERT_THROW(eval("throw \"foo\""), ThrownError);
+    }
+
+    TEST_F(PrimOpTest, abort) {
+        ASSERT_THROW(eval("abort \"abort\""), Abort);
+    }
+
+    TEST_F(PrimOpTest, ceil) {
+        auto v = eval("builtins.ceil 1.9");
+        ASSERT_THAT(v, IsIntEq(2));
+    }
+
+    TEST_F(PrimOpTest, floor) {
+        auto v = eval("builtins.floor 1.9");
+        ASSERT_THAT(v, IsIntEq(1));
+    }
+
+    TEST_F(PrimOpTest, tryEvalFailure) {
+        auto v = eval("builtins.tryEval (throw \"\")");
+        ASSERT_THAT(v, IsAttrsOfSize(2));
+        auto s = createSymbol("success");
+        auto p = v.attrs()->get(s);
+        ASSERT_NE(p, nullptr);
+        ASSERT_THAT(*p->value, IsFalse());
+    }
+
+    TEST_F(PrimOpTest, tryEvalSuccess) {
+        auto v = eval("builtins.tryEval 123");
+        ASSERT_THAT(v, IsAttrs());
+        auto s = createSymbol("success");
+        auto p = v.attrs()->get(s);
+        ASSERT_NE(p, nullptr);
+        ASSERT_THAT(*p->value, IsTrue());
+        s = createSymbol("value");
+        p = v.attrs()->get(s);
+        ASSERT_NE(p, nullptr);
+        ASSERT_THAT(*p->value, IsIntEq(123));
+    }
+
+    TEST_F(PrimOpTest, getEnv) {
+        setEnv("_NIX_UNIT_TEST_ENV_VALUE", "test value");
+        auto v = eval("builtins.getEnv \"_NIX_UNIT_TEST_ENV_VALUE\"");
+        ASSERT_THAT(v, IsStringEq("test value"));
+    }
+
+    TEST_F(PrimOpTest, seq) {
+        ASSERT_THROW(eval("let x = throw \"test\"; in builtins.seq x { }"), ThrownError);
+    }
+
+    TEST_F(PrimOpTest, seqNotDeep) {
+        auto v = eval("let x = { z =  throw \"test\"; }; in builtins.seq x { }");
+        ASSERT_THAT(v, IsAttrs());
+    }
+
+    TEST_F(PrimOpTest, deepSeq) {
+        ASSERT_THROW(eval("let x = { z =  throw \"test\"; }; in builtins.deepSeq x { }"), ThrownError);
+    }
+
+    TEST_F(PrimOpTest, trace) {
+        CaptureLogging l;
+        auto v = eval("builtins.trace \"test string 123\" 123");
+        ASSERT_THAT(v, IsIntEq(123));
+        auto text = l.get();
+        ASSERT_NE(text.find("test string 123"), std::string::npos);
+    }
+
+    TEST_F(PrimOpTest, placeholder) {
+        auto v = eval("builtins.placeholder \"out\"");
+        ASSERT_THAT(v, IsStringEq("/1rz4g4znpzjwh1xymhjpm42vipw92pr73vdgl6xs1hycac8kf2n9"));
+    }
+
+    TEST_F(PrimOpTest, baseNameOf) {
+        auto v = eval("builtins.baseNameOf /some/path");
+        ASSERT_THAT(v, IsStringEq("path"));
+    }
+
+    TEST_F(PrimOpTest, dirOf) {
+        auto v = eval("builtins.dirOf /some/path");
+        ASSERT_THAT(v, IsPathEq("/some"));
+    }
+
+    TEST_F(PrimOpTest, attrValues) {
+        auto v = eval("builtins.attrValues { x = \"foo\";  a = 1; }");
+        ASSERT_THAT(v, IsListOfSize(2));
+        ASSERT_THAT(*v.listElems()[0], IsIntEq(1));
+        ASSERT_THAT(*v.listElems()[1], IsStringEq("foo"));
+    }
+
+    TEST_F(PrimOpTest, getAttr) {
+        auto v = eval("builtins.getAttr \"x\" { x = \"foo\"; }");
+        ASSERT_THAT(v, IsStringEq("foo"));
+    }
+
+    TEST_F(PrimOpTest, getAttrNotFound) {
+        // FIXME: TypeError is really bad here, also the error wording is worse
+        // than on Nix <=2.3
+        ASSERT_THROW(eval("builtins.getAttr \"y\" { }"), TypeError);
+    }
+
+    TEST_F(PrimOpTest, unsafeGetAttrPos) {
+        state.corepkgsFS->addFile(CanonPath("foo.nix"), "\n\r\n\r{ y = \"x\"; }");
+
+        auto expr = "builtins.unsafeGetAttrPos \"y\" (import <nix/foo.nix>)";
+        auto v = eval(expr);
+        ASSERT_THAT(v, IsAttrsOfSize(3));
+
+        auto file = v.attrs()->find(createSymbol("file"));
+        ASSERT_NE(file, nullptr);
+        ASSERT_THAT(*file->value, IsString());
+        auto s = baseNameOf(file->value->string_view());
+        ASSERT_EQ(s, "foo.nix");
+
+        auto line = v.attrs()->find(createSymbol("line"));
+        ASSERT_NE(line, nullptr);
+        state.forceValue(*line->value, noPos);
+        ASSERT_THAT(*line->value, IsIntEq(4));
+
+        auto column = v.attrs()->find(createSymbol("column"));
+        ASSERT_NE(column, nullptr);
+        state.forceValue(*column->value, noPos);
+        ASSERT_THAT(*column->value, IsIntEq(3));
+    }
+
+    TEST_F(PrimOpTest, hasAttr) {
+        auto v = eval("builtins.hasAttr \"x\" { x = 1; }");
+        ASSERT_THAT(v, IsTrue());
+    }
+
+    TEST_F(PrimOpTest, hasAttrNotFound) {
+        auto v = eval("builtins.hasAttr \"x\" { }");
+        ASSERT_THAT(v, IsFalse());
+    }
+
+    TEST_F(PrimOpTest, isAttrs) {
+        auto v = eval("builtins.isAttrs {}");
+        ASSERT_THAT(v, IsTrue());
+    }
+
+    TEST_F(PrimOpTest, isAttrsFalse) {
+        auto v = eval("builtins.isAttrs null");
+        ASSERT_THAT(v, IsFalse());
+    }
+
+    TEST_F(PrimOpTest, removeAttrs) {
+        auto v = eval("builtins.removeAttrs { x = 1; } [\"x\"]");
+        ASSERT_THAT(v, IsAttrsOfSize(0));
+    }
+
+    TEST_F(PrimOpTest, removeAttrsRetains) {
+        auto v = eval("builtins.removeAttrs { x = 1; y = 2; } [\"x\"]");
+        ASSERT_THAT(v, IsAttrsOfSize(1));
+        ASSERT_NE(v.attrs()->find(createSymbol("y")), nullptr);
+    }
+
+    TEST_F(PrimOpTest, listToAttrsEmptyList) {
+        auto v = eval("builtins.listToAttrs []");
+        ASSERT_THAT(v, IsAttrsOfSize(0));
+        ASSERT_EQ(v.type(), nAttrs);
+        ASSERT_EQ(v.attrs()->size(), 0);
+    }
+
+    TEST_F(PrimOpTest, listToAttrsNotFieldName) {
+        ASSERT_THROW(eval("builtins.listToAttrs [{}]"), Error);
+    }
+
+    TEST_F(PrimOpTest, listToAttrs) {
+        auto v = eval("builtins.listToAttrs [ { name = \"key\"; value = 123; } ]");
+        ASSERT_THAT(v, IsAttrsOfSize(1));
+        auto key = v.attrs()->find(createSymbol("key"));
+        ASSERT_NE(key, nullptr);
+        ASSERT_THAT(*key->value, IsIntEq(123));
+    }
+
+    TEST_F(PrimOpTest, intersectAttrs) {
+        auto v = eval("builtins.intersectAttrs { a = 1; b = 2; } { b = 3; c = 4; }");
+        ASSERT_THAT(v, IsAttrsOfSize(1));
+        auto b = v.attrs()->find(createSymbol("b"));
+        ASSERT_NE(b, nullptr);
+        ASSERT_THAT(*b->value, IsIntEq(3));
+    }
+
+    TEST_F(PrimOpTest, catAttrs) {
+        auto v = eval("builtins.catAttrs \"a\" [{a = 1;} {b = 0;} {a = 2;}]");
+        ASSERT_THAT(v, IsListOfSize(2));
+        ASSERT_THAT(*v.listElems()[0], IsIntEq(1));
+        ASSERT_THAT(*v.listElems()[1], IsIntEq(2));
+    }
+
+    TEST_F(PrimOpTest, functionArgs) {
+        auto v = eval("builtins.functionArgs ({ x, y ? 123}: 1)");
+        ASSERT_THAT(v, IsAttrsOfSize(2));
+
+        auto x = v.attrs()->find(createSymbol("x"));
+        ASSERT_NE(x, nullptr);
+        ASSERT_THAT(*x->value, IsFalse());
+
+        auto y = v.attrs()->find(createSymbol("y"));
+        ASSERT_NE(y, nullptr);
+        ASSERT_THAT(*y->value, IsTrue());
+    }
+
+    TEST_F(PrimOpTest, mapAttrs) {
+        auto v = eval("builtins.mapAttrs (name: value: value * 10) { a = 1; b = 2; }");
+        ASSERT_THAT(v, IsAttrsOfSize(2));
+
+        auto a = v.attrs()->find(createSymbol("a"));
+        ASSERT_NE(a, nullptr);
+        ASSERT_THAT(*a->value, IsThunk());
+        state.forceValue(*a->value, noPos);
+        ASSERT_THAT(*a->value, IsIntEq(10));
+
+        auto b = v.attrs()->find(createSymbol("b"));
+        ASSERT_NE(b, nullptr);
+        ASSERT_THAT(*b->value, IsThunk());
+        state.forceValue(*b->value, noPos);
+        ASSERT_THAT(*b->value, IsIntEq(20));
+    }
+
+    TEST_F(PrimOpTest, isList) {
+        auto v = eval("builtins.isList []");
+        ASSERT_THAT(v, IsTrue());
+    }
+
+    TEST_F(PrimOpTest, isListFalse) {
+        auto v = eval("builtins.isList null");
+        ASSERT_THAT(v, IsFalse());
+    }
+
+    TEST_F(PrimOpTest, elemtAt) {
+        auto v = eval("builtins.elemAt [0 1 2 3] 3");
+        ASSERT_THAT(v, IsIntEq(3));
+    }
+
+    TEST_F(PrimOpTest, elemtAtOutOfBounds) {
+        ASSERT_THROW(eval("builtins.elemAt [0 1 2 3] 5"), Error);
+    }
+
+    TEST_F(PrimOpTest, head) {
+        auto v = eval("builtins.head [ 3 2 1 0 ]");
+        ASSERT_THAT(v, IsIntEq(3));
+    }
+
+    TEST_F(PrimOpTest, headEmpty) {
+        ASSERT_THROW(eval("builtins.head [ ]"), Error);
+    }
+
+    TEST_F(PrimOpTest, headWrongType) {
+        ASSERT_THROW(eval("builtins.head { }"), Error);
+    }
+
+    TEST_F(PrimOpTest, tail) {
+        auto v = eval("builtins.tail [ 3 2 1 0 ]");
+        ASSERT_THAT(v, IsListOfSize(3));
+        for (const auto [n, elem] : enumerate(v.listItems()))
+            ASSERT_THAT(*elem, IsIntEq(2 - static_cast<int>(n)));
+    }
+
+    TEST_F(PrimOpTest, tailEmpty) {
+        ASSERT_THROW(eval("builtins.tail []"), Error);
+    }
+
+    TEST_F(PrimOpTest, map) {
+        auto v = eval("map (x: \"foo\" + x) [ \"bar\" \"bla\" \"abc\" ]");
+        ASSERT_THAT(v, IsListOfSize(3));
+        auto elem = v.listElems()[0];
+        ASSERT_THAT(*elem, IsThunk());
+        state.forceValue(*elem, noPos);
+        ASSERT_THAT(*elem, IsStringEq("foobar"));
+
+        elem = v.listElems()[1];
+        ASSERT_THAT(*elem, IsThunk());
+        state.forceValue(*elem, noPos);
+        ASSERT_THAT(*elem, IsStringEq("foobla"));
+
+        elem = v.listElems()[2];
+        ASSERT_THAT(*elem, IsThunk());
+        state.forceValue(*elem, noPos);
+        ASSERT_THAT(*elem, IsStringEq("fooabc"));
+    }
+
+    TEST_F(PrimOpTest, filter) {
+        auto v = eval("builtins.filter (x: x == 2) [ 3 2 3 2 3 2 ]");
+        ASSERT_THAT(v, IsListOfSize(3));
+        for (const auto elem : v.listItems())
+            ASSERT_THAT(*elem, IsIntEq(2));
+    }
+
+    TEST_F(PrimOpTest, elemTrue) {
+        auto v = eval("builtins.elem 3 [ 1 2 3 4 5 ]");
+        ASSERT_THAT(v, IsTrue());
+    }
+
+    TEST_F(PrimOpTest, elemFalse) {
+        auto v = eval("builtins.elem 6 [ 1 2 3 4 5 ]");
+        ASSERT_THAT(v, IsFalse());
+    }
+
+    TEST_F(PrimOpTest, concatLists) {
+        auto v = eval("builtins.concatLists [[1 2] [3 4]]");
+        ASSERT_THAT(v, IsListOfSize(4));
+        for (const auto [i, elem] : enumerate(v.listItems()))
+            ASSERT_THAT(*elem, IsIntEq(static_cast<int>(i)+1));
+    }
+
+    TEST_F(PrimOpTest, length) {
+        auto v = eval("builtins.length [ 1 2 3 ]");
+        ASSERT_THAT(v, IsIntEq(3));
+    }
+
+    TEST_F(PrimOpTest, foldStrict) {
+        auto v = eval("builtins.foldl' (a: b: a + b) 0 [1 2 3]");
+        ASSERT_THAT(v, IsIntEq(6));
+    }
+
+    TEST_F(PrimOpTest, anyTrue) {
+        auto v = eval("builtins.any (x: x == 2) [ 1 2 3 ]");
+        ASSERT_THAT(v, IsTrue());
+    }
+
+    TEST_F(PrimOpTest, anyFalse) {
+        auto v = eval("builtins.any (x: x == 5) [ 1 2 3 ]");
+        ASSERT_THAT(v, IsFalse());
+    }
+
+    TEST_F(PrimOpTest, allTrue) {
+        auto v = eval("builtins.all (x: x > 0) [ 1 2 3 ]");
+        ASSERT_THAT(v, IsTrue());
+    }
+
+    TEST_F(PrimOpTest, allFalse) {
+        auto v = eval("builtins.all (x: x <= 0) [ 1 2 3 ]");
+        ASSERT_THAT(v, IsFalse());
+    }
+
+    TEST_F(PrimOpTest, genList) {
+        auto v = eval("builtins.genList (x: x + 1) 3");
+        ASSERT_EQ(v.type(), nList);
+        ASSERT_EQ(v.listSize(), 3);
+        for (const auto [i, elem] : enumerate(v.listItems())) {
+            ASSERT_THAT(*elem, IsThunk());
+            state.forceValue(*elem, noPos);
+            ASSERT_THAT(*elem, IsIntEq(static_cast<int>(i)+1));
+        }
+    }
+
+    TEST_F(PrimOpTest, sortLessThan) {
+        auto v = eval("builtins.sort builtins.lessThan [ 483 249 526 147 42 77 ]");
+        ASSERT_EQ(v.type(), nList);
+        ASSERT_EQ(v.listSize(), 6);
+
+        const std::vector<int> numbers = { 42, 77, 147, 249, 483, 526 };
+        for (const auto [n, elem] : enumerate(v.listItems()))
+            ASSERT_THAT(*elem, IsIntEq(numbers[n]));
+    }
+
+    TEST_F(PrimOpTest, partition) {
+        auto v = eval("builtins.partition (x: x > 10) [1 23 9 3 42]");
+        ASSERT_THAT(v, IsAttrsOfSize(2));
+
+        auto right = v.attrs()->get(createSymbol("right"));
+        ASSERT_NE(right, nullptr);
+        ASSERT_THAT(*right->value, IsListOfSize(2));
+        ASSERT_THAT(*right->value->listElems()[0], IsIntEq(23));
+        ASSERT_THAT(*right->value->listElems()[1], IsIntEq(42));
+
+        auto wrong = v.attrs()->get(createSymbol("wrong"));
+        ASSERT_NE(wrong, nullptr);
+        ASSERT_EQ(wrong->value->type(), nList);
+        ASSERT_EQ(wrong->value->listSize(), 3);
+        ASSERT_THAT(*wrong->value, IsListOfSize(3));
+        ASSERT_THAT(*wrong->value->listElems()[0], IsIntEq(1));
+        ASSERT_THAT(*wrong->value->listElems()[1], IsIntEq(9));
+        ASSERT_THAT(*wrong->value->listElems()[2], IsIntEq(3));
+    }
+
+    TEST_F(PrimOpTest, concatMap) {
+        auto v = eval("builtins.concatMap (x: x ++ [0]) [ [1 2] [3 4] ]");
+        ASSERT_EQ(v.type(), nList);
+        ASSERT_EQ(v.listSize(), 6);
+
+        const std::vector<int> numbers = { 1, 2, 0, 3, 4, 0 };
+        for (const auto [n, elem] : enumerate(v.listItems()))
+            ASSERT_THAT(*elem, IsIntEq(numbers[n]));
+    }
+
+    TEST_F(PrimOpTest, addInt) {
+        auto v = eval("builtins.add 3 5");
+        ASSERT_THAT(v, IsIntEq(8));
+    }
+
+    TEST_F(PrimOpTest, addFloat) {
+        auto v = eval("builtins.add 3.0 5.0");
+        ASSERT_THAT(v, IsFloatEq(8.0));
+    }
+
+    TEST_F(PrimOpTest, addFloatToInt) {
+        auto v = eval("builtins.add 3.0 5");
+        ASSERT_THAT(v, IsFloatEq(8.0));
+
+        v = eval("builtins.add 3 5.0");
+        ASSERT_THAT(v, IsFloatEq(8.0));
+    }
+
+    TEST_F(PrimOpTest, subInt) {
+        auto v = eval("builtins.sub 5 2");
+        ASSERT_THAT(v, IsIntEq(3));
+    }
+
+    TEST_F(PrimOpTest, subFloat) {
+        auto v = eval("builtins.sub 5.0 2.0");
+        ASSERT_THAT(v, IsFloatEq(3.0));
+    }
+
+    TEST_F(PrimOpTest, subFloatFromInt) {
+        auto v = eval("builtins.sub 5.0 2");
+        ASSERT_THAT(v, IsFloatEq(3.0));
+
+        v = eval("builtins.sub 4 2.0");
+        ASSERT_THAT(v, IsFloatEq(2.0));
+    }
+
+    TEST_F(PrimOpTest, mulInt) {
+        auto v = eval("builtins.mul 3 5");
+        ASSERT_THAT(v, IsIntEq(15));
+    }
+
+    TEST_F(PrimOpTest, mulFloat) {
+        auto v = eval("builtins.mul 3.0 5.0");
+        ASSERT_THAT(v, IsFloatEq(15.0));
+    }
+
+    TEST_F(PrimOpTest, mulFloatMixed) {
+        auto v = eval("builtins.mul 3 5.0");
+        ASSERT_THAT(v, IsFloatEq(15.0));
+
+        v = eval("builtins.mul 2.0 5");
+        ASSERT_THAT(v, IsFloatEq(10.0));
+    }
+
+    TEST_F(PrimOpTest, divInt) {
+        auto v = eval("builtins.div 5 (-1)");
+        ASSERT_THAT(v, IsIntEq(-5));
+    }
+
+    TEST_F(PrimOpTest, divIntZero) {
+        ASSERT_THROW(eval("builtins.div 5 0"), EvalError);
+    }
+
+    TEST_F(PrimOpTest, divFloat) {
+        auto v = eval("builtins.div 5.0 (-1)");
+        ASSERT_THAT(v, IsFloatEq(-5.0));
+    }
+
+    TEST_F(PrimOpTest, divFloatZero) {
+        ASSERT_THROW(eval("builtins.div 5.0 0.0"), EvalError);
+    }
+
+    TEST_F(PrimOpTest, bitOr) {
+        auto v = eval("builtins.bitOr 1 2");
+        ASSERT_THAT(v, IsIntEq(3));
+    }
+
+    TEST_F(PrimOpTest, bitXor) {
+        auto v = eval("builtins.bitXor 3 2");
+        ASSERT_THAT(v, IsIntEq(1));
+    }
+
+    TEST_F(PrimOpTest, lessThanFalse) {
+        auto v = eval("builtins.lessThan 3 1");
+        ASSERT_THAT(v, IsFalse());
+    }
+
+    TEST_F(PrimOpTest, lessThanTrue) {
+        auto v = eval("builtins.lessThan 1 3");
+        ASSERT_THAT(v, IsTrue());
+    }
+
+    TEST_F(PrimOpTest, toStringAttrsThrows) {
+        ASSERT_THROW(eval("builtins.toString {}"), EvalError);
+    }
+
+    TEST_F(PrimOpTest, toStringLambdaThrows) {
+        ASSERT_THROW(eval("builtins.toString (x: x)"), EvalError);
+    }
+
+    class ToStringPrimOpTest :
+        public PrimOpTest,
+        public testing::WithParamInterface<std::tuple<std::string, std::string_view>>
+        {};
+
+    TEST_P(ToStringPrimOpTest, toString) {
+        const auto [input, output] = GetParam();
+        auto v = eval(input);
+        ASSERT_THAT(v, IsStringEq(output));
+    }
+
+#define CASE(input, output) (std::make_tuple(std::string_view("builtins.toString " input), std::string_view(output)))
+    INSTANTIATE_TEST_SUITE_P(
+            toString,
+            ToStringPrimOpTest,
+            testing::Values(
+                CASE(R"("foo")", "foo"),
+                CASE(R"(1)", "1"),
+                CASE(R"([1 2 3])", "1 2 3"),
+                CASE(R"(.123)", "0.123000"),
+                CASE(R"(true)", "1"),
+                CASE(R"(false)", ""),
+                CASE(R"(null)", ""),
+                CASE(R"({ v = "bar"; __toString = self: self.v; })", "bar"),
+                CASE(R"({ v = "bar"; __toString = self: self.v; outPath = "foo"; })", "bar"),
+                CASE(R"({ outPath = "foo"; })", "foo"),
+                CASE(R"(./test)", "/test")
+            )
+    );
+#undef CASE
+
+    TEST_F(PrimOpTest, substring){
+        auto v = eval("builtins.substring 0 3 \"nixos\"");
+        ASSERT_THAT(v, IsStringEq("nix"));
+    }
+
+    TEST_F(PrimOpTest, substringSmallerString){
+        auto v = eval("builtins.substring 0 3 \"n\"");
+        ASSERT_THAT(v, IsStringEq("n"));
+    }
+
+    TEST_F(PrimOpTest, substringEmptyString){
+        auto v = eval("builtins.substring 1 3 \"\"");
+        ASSERT_THAT(v, IsStringEq(""));
+    }
+
+    TEST_F(PrimOpTest, stringLength) {
+        auto v = eval("builtins.stringLength \"123\"");
+        ASSERT_THAT(v, IsIntEq(3));
+    }
+    TEST_F(PrimOpTest, hashStringMd5) {
+        auto v = eval("builtins.hashString \"md5\" \"asdf\"");
+        ASSERT_THAT(v, IsStringEq("912ec803b2ce49e4a541068d495ab570"));
+    }
+
+    TEST_F(PrimOpTest, hashStringSha1) {
+        auto v = eval("builtins.hashString \"sha1\" \"asdf\"");
+        ASSERT_THAT(v, IsStringEq("3da541559918a808c2402bba5012f6c60b27661c"));
+    }
+
+    TEST_F(PrimOpTest, hashStringSha256) {
+        auto v = eval("builtins.hashString \"sha256\" \"asdf\"");
+        ASSERT_THAT(v, IsStringEq("f0e4c2f76c58916ec258f246851bea091d14d4247a2fc3e18694461b1816e13b"));
+    }
+
+    TEST_F(PrimOpTest, hashStringSha512) {
+        auto v = eval("builtins.hashString \"sha512\" \"asdf\"");
+        ASSERT_THAT(v, IsStringEq("401b09eab3c013d4ca54922bb802bec8fd5318192b0a75f201d8b3727429080fb337591abd3e44453b954555b7a0812e1081c39b740293f765eae731f5a65ed1"));
+    }
+
+    TEST_F(PrimOpTest, hashStringInvalidHashAlgorithm) {
+        ASSERT_THROW(eval("builtins.hashString \"foobar\" \"asdf\""), Error);
+    }
+
+    TEST_F(PrimOpTest, nixPath) {
+        auto v = eval("builtins.nixPath");
+        ASSERT_EQ(v.type(), nList);
+        // We can't test much more as currently the EvalSettings are a global
+        // that we can't easily swap / replace
+    }
+
+    TEST_F(PrimOpTest, langVersion) {
+        auto v = eval("builtins.langVersion");
+        ASSERT_EQ(v.type(), nInt);
+    }
+
+    TEST_F(PrimOpTest, storeDir) {
+        auto v = eval("builtins.storeDir");
+        ASSERT_THAT(v, IsStringEq(settings.nixStore));
+    }
+
+    TEST_F(PrimOpTest, nixVersion) {
+        auto v = eval("builtins.nixVersion");
+        ASSERT_THAT(v, IsStringEq(nixVersion));
+    }
+
+    TEST_F(PrimOpTest, currentSystem) {
+        auto v = eval("builtins.currentSystem");
+        ASSERT_THAT(v, IsStringEq(evalSettings.getCurrentSystem()));
+    }
+
+    TEST_F(PrimOpTest, derivation) {
+        auto v = eval("derivation");
+        ASSERT_EQ(v.type(), nFunction);
+        ASSERT_TRUE(v.isLambda());
+        ASSERT_NE(v.payload.lambda.fun, nullptr);
+        ASSERT_TRUE(v.payload.lambda.fun->hasFormals());
+    }
+
+    TEST_F(PrimOpTest, currentTime) {
+        auto v = eval("builtins.currentTime");
+        ASSERT_EQ(v.type(), nInt);
+        ASSERT_TRUE(v.integer() > 0);
+    }
+
+    TEST_F(PrimOpTest, splitVersion) {
+        auto v = eval("builtins.splitVersion \"1.2.3git\"");
+        ASSERT_THAT(v, IsListOfSize(4));
+
+        const std::vector<std::string_view> strings = { "1", "2", "3", "git" };
+        for (const auto [n, p] : enumerate(v.listItems()))
+            ASSERT_THAT(*p, IsStringEq(strings[n]));
+    }
+
+    class CompareVersionsPrimOpTest :
+        public PrimOpTest,
+        public testing::WithParamInterface<std::tuple<std::string, const int>>
+        {};
+
+    TEST_P(CompareVersionsPrimOpTest, compareVersions) {
+        auto [expression, expectation] = GetParam();
+        auto v = eval(expression);
+        ASSERT_THAT(v, IsIntEq(expectation));
+    }
+
+#define CASE(a, b, expected) (std::make_tuple("builtins.compareVersions \"" #a "\" \"" #b "\"", expected))
+    INSTANTIATE_TEST_SUITE_P(
+            compareVersions,
+            CompareVersionsPrimOpTest,
+            testing::Values(
+                // The first two are weird cases. Intuition tells they should
+                // be the same but they aren't.
+                CASE(1.0, 1.0.0, -1),
+                CASE(1.0.0, 1.0, 1),
+                // the following are from the nix-env manual:
+                CASE(1.0, 2.3, -1),
+                CASE(2.1, 2.3, -1),
+                CASE(2.3, 2.3, 0),
+                CASE(2.5, 2.3, 1),
+                CASE(3.1, 2.3, 1),
+                CASE(2.3.1, 2.3, 1),
+                CASE(2.3.1, 2.3a, 1),
+                CASE(2.3pre1, 2.3, -1),
+                CASE(2.3pre3, 2.3pre12, -1),
+                CASE(2.3a, 2.3c, -1),
+                CASE(2.3pre1, 2.3c, -1),
+                CASE(2.3pre1, 2.3q, -1)
+            )
+    );
+#undef CASE
+
+
+  class ParseDrvNamePrimOpTest :
+      public PrimOpTest,
+      public testing::WithParamInterface<std::tuple<std::string, std::string_view, std::string_view>>
+      {};
+
+    TEST_P(ParseDrvNamePrimOpTest, parseDrvName) {
+        auto [input, expectedName, expectedVersion] = GetParam();
+        const auto expr = fmt("builtins.parseDrvName \"%1%\"", input);
+        auto v = eval(expr);
+        ASSERT_THAT(v, IsAttrsOfSize(2));
+
+        auto name = v.attrs()->find(createSymbol("name"));
+        ASSERT_TRUE(name);
+        ASSERT_THAT(*name->value, IsStringEq(expectedName));
+
+        auto version = v.attrs()->find(createSymbol("version"));
+        ASSERT_TRUE(version);
+        ASSERT_THAT(*version->value, IsStringEq(expectedVersion));
+    }
+
+    INSTANTIATE_TEST_SUITE_P(
+            parseDrvName,
+            ParseDrvNamePrimOpTest,
+            testing::Values(
+                std::make_tuple("nix-0.12pre12876", "nix", "0.12pre12876"),
+                std::make_tuple("a-b-c-1234pre5+git", "a-b-c", "1234pre5+git")
+            )
+    );
+
+    TEST_F(PrimOpTest, replaceStrings) {
+        // FIXME: add a test that verifies the string context is as expected
+        auto v = eval("builtins.replaceStrings [\"oo\" \"a\"] [\"a\" \"i\"] \"foobar\"");
+        ASSERT_EQ(v.type(), nString);
+        ASSERT_EQ(v.string_view(), "fabir");
+    }
+
+    TEST_F(PrimOpTest, concatStringsSep) {
+        // FIXME: add a test that verifies the string context is as expected
+        auto v = eval("builtins.concatStringsSep \"%\" [\"foo\" \"bar\" \"baz\"]");
+        ASSERT_EQ(v.type(), nString);
+        ASSERT_EQ(v.string_view(), "foo%bar%baz");
+    }
+
+    TEST_F(PrimOpTest, split1) {
+        // v = [ "" [ "a" ] "c" ]
+        auto v = eval("builtins.split \"(a)b\" \"abc\"");
+        ASSERT_THAT(v, IsListOfSize(3));
+
+        ASSERT_THAT(*v.listElems()[0], IsStringEq(""));
+
+        ASSERT_THAT(*v.listElems()[1], IsListOfSize(1));
+        ASSERT_THAT(*v.listElems()[1]->listElems()[0], IsStringEq("a"));
+
+        ASSERT_THAT(*v.listElems()[2], IsStringEq("c"));
+    }
+
+    TEST_F(PrimOpTest, split2) {
+        // v is expected to be a list [ "" [ "a" ] "b" [ "c"] "" ]
+        auto v = eval("builtins.split \"([ac])\" \"abc\"");
+        ASSERT_THAT(v, IsListOfSize(5));
+
+        ASSERT_THAT(*v.listElems()[0], IsStringEq(""));
+
+        ASSERT_THAT(*v.listElems()[1], IsListOfSize(1));
+        ASSERT_THAT(*v.listElems()[1]->listElems()[0], IsStringEq("a"));
+
+        ASSERT_THAT(*v.listElems()[2], IsStringEq("b"));
+
+        ASSERT_THAT(*v.listElems()[3], IsListOfSize(1));
+        ASSERT_THAT(*v.listElems()[3]->listElems()[0], IsStringEq("c"));
+
+        ASSERT_THAT(*v.listElems()[4], IsStringEq(""));
+    }
+
+    TEST_F(PrimOpTest, split3) {
+        auto v = eval("builtins.split \"(a)|(c)\" \"abc\"");
+        ASSERT_THAT(v, IsListOfSize(5));
+
+        // First list element
+        ASSERT_THAT(*v.listElems()[0], IsStringEq(""));
+
+        // 2nd list element is a list [ "" null ]
+        ASSERT_THAT(*v.listElems()[1], IsListOfSize(2));
+        ASSERT_THAT(*v.listElems()[1]->listElems()[0], IsStringEq("a"));
+        ASSERT_THAT(*v.listElems()[1]->listElems()[1], IsNull());
+
+        // 3rd element
+        ASSERT_THAT(*v.listElems()[2], IsStringEq("b"));
+
+        // 4th element is a list: [ null "c" ]
+        ASSERT_THAT(*v.listElems()[3], IsListOfSize(2));
+        ASSERT_THAT(*v.listElems()[3]->listElems()[0], IsNull());
+        ASSERT_THAT(*v.listElems()[3]->listElems()[1], IsStringEq("c"));
+
+        // 5th element is the empty string
+        ASSERT_THAT(*v.listElems()[4], IsStringEq(""));
+    }
+
+    TEST_F(PrimOpTest, split4) {
+        auto v = eval("builtins.split \"([[:upper:]]+)\" \" FOO \"");
+        ASSERT_THAT(v, IsListOfSize(3));
+        auto first = v.listElems()[0];
+        auto second = v.listElems()[1];
+        auto third = v.listElems()[2];
+
+        ASSERT_THAT(*first, IsStringEq(" "));
+
+        ASSERT_THAT(*second, IsListOfSize(1));
+        ASSERT_THAT(*second->listElems()[0], IsStringEq("FOO"));
+
+        ASSERT_THAT(*third, IsStringEq(" "));
+    }
+
+    TEST_F(PrimOpTest, match1) {
+        auto v = eval("builtins.match \"ab\" \"abc\"");
+        ASSERT_THAT(v, IsNull());
+    }
+
+    TEST_F(PrimOpTest, match2) {
+        auto v = eval("builtins.match \"abc\" \"abc\"");
+        ASSERT_THAT(v, IsListOfSize(0));
+    }
+
+    TEST_F(PrimOpTest, match3) {
+        auto v = eval("builtins.match \"a(b)(c)\" \"abc\"");
+        ASSERT_THAT(v, IsListOfSize(2));
+        ASSERT_THAT(*v.listElems()[0], IsStringEq("b"));
+        ASSERT_THAT(*v.listElems()[1], IsStringEq("c"));
+    }
+
+    TEST_F(PrimOpTest, match4) {
+        auto v = eval("builtins.match \"[[:space:]]+([[:upper:]]+)[[:space:]]+\" \"  FOO   \"");
+        ASSERT_THAT(v, IsListOfSize(1));
+        ASSERT_THAT(*v.listElems()[0], IsStringEq("FOO"));
+    }
+
+    TEST_F(PrimOpTest, match5) {
+        // The regex "\\{}" is valid and matches the string "{}".
+        // Caused a regression before when trying to switch from std::regex to boost::regex.
+        // See https://github.com/NixOS/nix/pull/7762#issuecomment-1834303659
+        auto v = eval("builtins.match \"\\\\{}\" \"{}\"");
+        ASSERT_THAT(v, IsListOfSize(0));
+    }
+
+    TEST_F(PrimOpTest, attrNames) {
+        auto v = eval("builtins.attrNames { x = 1; y = 2; z = 3; a = 2; }");
+        ASSERT_THAT(v, IsListOfSize(4));
+
+        // ensure that the list is sorted
+        const std::vector<std::string_view> expected { "a", "x", "y", "z" };
+        for (const auto [n, elem] : enumerate(v.listItems()))
+            ASSERT_THAT(*elem, IsStringEq(expected[n]));
+    }
+
+    TEST_F(PrimOpTest, genericClosure_not_strict) {
+        // Operator should not be used when startSet is empty
+        auto v = eval("builtins.genericClosure { startSet = []; }");
+        ASSERT_THAT(v, IsListOfSize(0));
+    }
+} /* namespace nix */

src/libexpr-tests/search-path.cc

@@ -0,0 +1,90 @@
+#include <gtest/gtest.h>
+#include <gmock/gmock.h>
+
+#include "search-path.hh"
+
+namespace nix {
+
+TEST(LookupPathElem, parse_justPath) {
+    ASSERT_EQ(
+        LookupPath::Elem::parse("foo"),
+        (LookupPath::Elem {
+            .prefix = LookupPath::Prefix { .s = "" },
+            .path = LookupPath::Path { .s = "foo" },
+        }));
+}
+
+TEST(LookupPathElem, parse_emptyPrefix) {
+    ASSERT_EQ(
+        LookupPath::Elem::parse("=foo"),
+        (LookupPath::Elem {
+            .prefix = LookupPath::Prefix { .s = "" },
+            .path = LookupPath::Path { .s = "foo" },
+        }));
+}
+
+TEST(LookupPathElem, parse_oneEq) {
+    ASSERT_EQ(
+        LookupPath::Elem::parse("foo=bar"),
+        (LookupPath::Elem {
+            .prefix = LookupPath::Prefix { .s = "foo" },
+            .path = LookupPath::Path { .s = "bar" },
+        }));
+}
+
+TEST(LookupPathElem, parse_twoEqs) {
+    ASSERT_EQ(
+        LookupPath::Elem::parse("foo=bar=baz"),
+        (LookupPath::Elem {
+            .prefix = LookupPath::Prefix { .s = "foo" },
+            .path = LookupPath::Path { .s = "bar=baz" },
+        }));
+}
+
+
+TEST(LookupPathElem, suffixIfPotentialMatch_justPath) {
+    LookupPath::Prefix prefix { .s = "" };
+    ASSERT_EQ(prefix.suffixIfPotentialMatch("any/thing"), std::optional { "any/thing" });
+}
+
+TEST(LookupPathElem, suffixIfPotentialMatch_misleadingPrefix1) {
+    LookupPath::Prefix prefix { .s = "foo" };
+    ASSERT_EQ(prefix.suffixIfPotentialMatch("fooX"), std::nullopt);
+}
+
+TEST(LookupPathElem, suffixIfPotentialMatch_misleadingPrefix2) {
+    LookupPath::Prefix prefix { .s = "foo" };
+    ASSERT_EQ(prefix.suffixIfPotentialMatch("fooX/bar"), std::nullopt);
+}
+
+TEST(LookupPathElem, suffixIfPotentialMatch_partialPrefix) {
+    LookupPath::Prefix prefix { .s = "fooX" };
+    ASSERT_EQ(prefix.suffixIfPotentialMatch("foo"), std::nullopt);
+}
+
+TEST(LookupPathElem, suffixIfPotentialMatch_exactPrefix) {
+    LookupPath::Prefix prefix { .s = "foo" };
+    ASSERT_EQ(prefix.suffixIfPotentialMatch("foo"), std::optional { "" });
+}
+
+TEST(LookupPathElem, suffixIfPotentialMatch_multiKey) {
+    LookupPath::Prefix prefix { .s = "foo/bar" };
+    ASSERT_EQ(prefix.suffixIfPotentialMatch("foo/bar/baz"), std::optional { "baz" });
+}
+
+TEST(LookupPathElem, suffixIfPotentialMatch_trailingSlash) {
+    LookupPath::Prefix prefix { .s = "foo" };
+    ASSERT_EQ(prefix.suffixIfPotentialMatch("foo/"), std::optional { "" });
+}
+
+TEST(LookupPathElem, suffixIfPotentialMatch_trailingDoubleSlash) {
+    LookupPath::Prefix prefix { .s = "foo" };
+    ASSERT_EQ(prefix.suffixIfPotentialMatch("foo//"), std::optional { "/" });
+}
+
+TEST(LookupPathElem, suffixIfPotentialMatch_trailingPath) {
+    LookupPath::Prefix prefix { .s = "foo" };
+    ASSERT_EQ(prefix.suffixIfPotentialMatch("foo/bar/baz"), std::optional { "bar/baz" });
+}
+
+}

src/libexpr-tests/trivial.cc

@@ -0,0 +1,250 @@
+#include "tests/libexpr.hh"
+
+namespace nix {
+    // Testing of trivial expressions
+    class TrivialExpressionTest : public LibExprTest {};
+
+    TEST_F(TrivialExpressionTest, true) {
+        auto v = eval("true");
+        ASSERT_THAT(v, IsTrue());
+    }
+
+    TEST_F(TrivialExpressionTest, false) {
+        auto v = eval("false");
+        ASSERT_THAT(v, IsFalse());
+    }
+
+    TEST_F(TrivialExpressionTest, null) {
+        auto v = eval("null");
+        ASSERT_THAT(v, IsNull());
+    }
+
+    TEST_F(TrivialExpressionTest, 1) {
+        auto v = eval("1");
+        ASSERT_THAT(v, IsIntEq(1));
+    }
+
+    TEST_F(TrivialExpressionTest, 1plus1) {
+        auto v = eval("1+1");
+        ASSERT_THAT(v, IsIntEq(2));
+    }
+
+    TEST_F(TrivialExpressionTest, minus1) {
+        auto v = eval("-1");
+        ASSERT_THAT(v, IsIntEq(-1));
+    }
+
+    TEST_F(TrivialExpressionTest, 1minus1) {
+        auto v = eval("1-1");
+        ASSERT_THAT(v, IsIntEq(0));
+    }
+
+    TEST_F(TrivialExpressionTest, lambdaAdd) {
+        auto v = eval("let add = a: b: a + b; in add 1 2");
+        ASSERT_THAT(v, IsIntEq(3));
+    }
+
+    TEST_F(TrivialExpressionTest, list) {
+        auto v = eval("[]");
+        ASSERT_THAT(v, IsListOfSize(0));
+    }
+
+    TEST_F(TrivialExpressionTest, attrs) {
+        auto v = eval("{}");
+        ASSERT_THAT(v, IsAttrsOfSize(0));
+    }
+
+    TEST_F(TrivialExpressionTest, float) {
+        auto v = eval("1.234");
+        ASSERT_THAT(v, IsFloatEq(1.234));
+    }
+
+    TEST_F(TrivialExpressionTest, updateAttrs) {
+        auto v = eval("{ a = 1; } // { b = 2; a = 3; }");
+        ASSERT_THAT(v, IsAttrsOfSize(2));
+        auto a = v.attrs()->find(createSymbol("a"));
+        ASSERT_NE(a, nullptr);
+        ASSERT_THAT(*a->value, IsIntEq(3));
+
+        auto b = v.attrs()->find(createSymbol("b"));
+        ASSERT_NE(b, nullptr);
+        ASSERT_THAT(*b->value, IsIntEq(2));
+    }
+
+    TEST_F(TrivialExpressionTest, hasAttrOpFalse) {
+        auto v = eval("{} ? a");
+        ASSERT_THAT(v, IsFalse());
+    }
+
+    TEST_F(TrivialExpressionTest, hasAttrOpTrue) {
+        auto v = eval("{ a = 123; } ? a");
+        ASSERT_THAT(v, IsTrue());
+    }
+
+    TEST_F(TrivialExpressionTest, withFound) {
+        auto v = eval("with { a = 23; }; a");
+        ASSERT_THAT(v, IsIntEq(23));
+    }
+
+    TEST_F(TrivialExpressionTest, withNotFound) {
+        ASSERT_THROW(eval("with {}; a"), Error);
+    }
+
+    TEST_F(TrivialExpressionTest, withOverride) {
+        auto v = eval("with { a = 23; }; with { a = 42; }; a");
+        ASSERT_THAT(v, IsIntEq(42));
+    }
+
+    TEST_F(TrivialExpressionTest, letOverWith) {
+        auto v = eval("let a = 23; in with { a = 1; }; a");
+        ASSERT_THAT(v, IsIntEq(23));
+    }
+
+    TEST_F(TrivialExpressionTest, multipleLet) {
+        auto v = eval("let a = 23; in let a = 42; in a");
+        ASSERT_THAT(v, IsIntEq(42));
+    }
+
+    TEST_F(TrivialExpressionTest, defaultFunctionArgs) {
+        auto v = eval("({ a ? 123 }: a) {}");
+        ASSERT_THAT(v, IsIntEq(123));
+    }
+
+    TEST_F(TrivialExpressionTest, defaultFunctionArgsOverride) {
+        auto v = eval("({ a ? 123 }: a) { a = 5; }");
+        ASSERT_THAT(v, IsIntEq(5));
+    }
+
+    TEST_F(TrivialExpressionTest, defaultFunctionArgsCaptureBack) {
+        auto v = eval("({ a ? 123 }@args: args) {}");
+        ASSERT_THAT(v, IsAttrsOfSize(0));
+    }
+
+    TEST_F(TrivialExpressionTest, defaultFunctionArgsCaptureFront) {
+        auto v = eval("(args@{ a ? 123 }: args) {}");
+        ASSERT_THAT(v, IsAttrsOfSize(0));
+    }
+
+    TEST_F(TrivialExpressionTest, assertThrows) {
+        ASSERT_THROW(eval("let x = arg: assert arg == 1; 123; in x 2"), Error);
+    }
+
+    TEST_F(TrivialExpressionTest, assertPassed) {
+        auto v = eval("let x = arg: assert arg == 1; 123; in x 1");
+        ASSERT_THAT(v, IsIntEq(123));
+    }
+
+    class AttrSetMergeTrvialExpressionTest :
+        public TrivialExpressionTest,
+        public testing::WithParamInterface<const char*>
+        {};
+
+    TEST_P(AttrSetMergeTrvialExpressionTest, attrsetMergeLazy) {
+        // Usually Nix rejects duplicate keys in an attrset but it does allow
+        // so if it is an attribute set that contains disjoint sets of keys.
+        // The below is equivalent to `{a.b = 1; a.c = 2; }`.
+        // The attribute set `a` will be a Thunk at first as the attribuets
+        // have to be merged (or otherwise computed) and that is done in a lazy
+        // manner.
+
+        auto expr = GetParam();
+        auto v = eval(expr);
+        ASSERT_THAT(v, IsAttrsOfSize(1));
+
+        auto a = v.attrs()->find(createSymbol("a"));
+        ASSERT_NE(a, nullptr);
+
+        ASSERT_THAT(*a->value, IsThunk());
+        state.forceValue(*a->value, noPos);
+
+        ASSERT_THAT(*a->value, IsAttrsOfSize(2));
+
+        auto b = a->value->attrs()->find(createSymbol("b"));
+        ASSERT_NE(b, nullptr);
+        ASSERT_THAT(*b->value, IsIntEq(1));
+
+        auto c = a->value->attrs()->find(createSymbol("c"));
+        ASSERT_NE(c, nullptr);
+        ASSERT_THAT(*c->value, IsIntEq(2));
+    }
+
+    INSTANTIATE_TEST_SUITE_P(
+            attrsetMergeLazy,
+            AttrSetMergeTrvialExpressionTest,
+            testing::Values(
+                "{ a.b = 1; a.c = 2; }",
+                "{ a = { b = 1; }; a = { c = 2; }; }"
+            )
+    );
+
+    TEST_F(TrivialExpressionTest, functor) {
+        auto v = eval("{ __functor = self: arg: self.v + arg; v = 10; } 5");
+        ASSERT_THAT(v, IsIntEq(15));
+    }
+
+    TEST_F(TrivialExpressionTest, forwardPipe) {
+        auto v = eval("1 |> builtins.add 2 |> builtins.mul 3");
+        ASSERT_THAT(v, IsIntEq(9));
+    }
+
+    TEST_F(TrivialExpressionTest, backwardPipe) {
+        auto v = eval("builtins.add 1 <| builtins.mul 2 <| 3");
+        ASSERT_THAT(v, IsIntEq(7));
+    }
+
+    TEST_F(TrivialExpressionTest, forwardPipeEvaluationOrder) {
+        auto v = eval("1 |> null |> (x: 2)");
+        ASSERT_THAT(v, IsIntEq(2));
+    }
+
+    TEST_F(TrivialExpressionTest, backwardPipeEvaluationOrder) {
+        auto v = eval("(x: 1) <| null <| 2");
+        ASSERT_THAT(v, IsIntEq(1));
+    }
+
+    TEST_F(TrivialExpressionTest, differentPipeOperatorsDoNotAssociate) {
+        ASSERT_THROW(eval("(x: 1) <| 2 |> (x: 3)"), ParseError);
+    }
+
+    TEST_F(TrivialExpressionTest, differentPipeOperatorsParensLeft) {
+        auto v = eval("((x: 1) <| 2) |> (x: 3)");
+        ASSERT_THAT(v, IsIntEq(3));
+    }
+
+    TEST_F(TrivialExpressionTest, differentPipeOperatorsParensRight) {
+        auto v = eval("(x: 1) <| (2 |> (x: 3))");
+        ASSERT_THAT(v, IsIntEq(1));
+    }
+
+    TEST_F(TrivialExpressionTest, forwardPipeLowestPrecedence) {
+        auto v = eval("false -> true |> (x: !x)");
+        ASSERT_THAT(v, IsFalse());
+    }
+
+    TEST_F(TrivialExpressionTest, backwardPipeLowestPrecedence) {
+        auto v = eval("(x: !x) <| false -> true");
+        ASSERT_THAT(v, IsFalse());
+    }
+
+    TEST_F(TrivialExpressionTest, forwardPipeStrongerThanElse) {
+        auto v = eval("if true then 1 else 2 |> 3");
+        ASSERT_THAT(v, IsIntEq(1));
+    }
+
+    TEST_F(TrivialExpressionTest, backwardPipeStrongerThanElse) {
+        auto v = eval("if true then 1 else 2 <| 3");
+        ASSERT_THAT(v, IsIntEq(1));
+    }
+
+    TEST_F(TrivialExpressionTest, bindOr) {
+        auto v = eval("{ or = 1; }");
+        ASSERT_THAT(v, IsAttrsOfSize(1));
+        auto b = v.attrs()->find(createSymbol("or"));
+        ASSERT_NE(b, nullptr);
+        ASSERT_THAT(*b->value, IsIntEq(1));
+    }
+
+    TEST_F(TrivialExpressionTest, orCantBeUsed) {
+        ASSERT_THROW(eval("let or = 1; in or"), Error);
+    }
+} /* namespace nix */

src/libexpr-tests/value/context.cc

@@ -0,0 +1,132 @@
+#include <nlohmann/json.hpp>
+#include <gtest/gtest.h>
+#include <rapidcheck/gtest.h>
+
+#include "tests/path.hh"
+#include "tests/libexpr.hh"
+#include "tests/value/context.hh"
+
+namespace nix {
+
+// Test a few cases of invalid string context elements.
+
+TEST(NixStringContextElemTest, empty_invalid) {
+    EXPECT_THROW(
+        NixStringContextElem::parse(""),
+        BadNixStringContextElem);
+}
+
+TEST(NixStringContextElemTest, single_bang_invalid) {
+    EXPECT_THROW(
+        NixStringContextElem::parse("!"),
+        BadNixStringContextElem);
+}
+
+TEST(NixStringContextElemTest, double_bang_invalid) {
+    EXPECT_THROW(
+        NixStringContextElem::parse("!!/"),
+        BadStorePath);
+}
+
+TEST(NixStringContextElemTest, eq_slash_invalid) {
+    EXPECT_THROW(
+        NixStringContextElem::parse("=/"),
+        BadStorePath);
+}
+
+TEST(NixStringContextElemTest, slash_invalid) {
+    EXPECT_THROW(
+        NixStringContextElem::parse("/"),
+        BadStorePath);
+}
+
+/**
+ * Round trip (string <-> data structure) test for
+ * `NixStringContextElem::Opaque`.
+ */
+TEST(NixStringContextElemTest, opaque) {
+    std::string_view opaque = "g1w7hy3qg1w7hy3qg1w7hy3qg1w7hy3q-x";
+    auto elem = NixStringContextElem::parse(opaque);
+    auto * p = std::get_if<NixStringContextElem::Opaque>(&elem.raw);
+    ASSERT_TRUE(p);
+    ASSERT_EQ(p->path, StorePath { opaque });
+    ASSERT_EQ(elem.to_string(), opaque);
+}
+
+/**
+ * Round trip (string <-> data structure) test for
+ * `NixStringContextElem::DrvDeep`.
+ */
+TEST(NixStringContextElemTest, drvDeep) {
+    std::string_view drvDeep = "=g1w7hy3qg1w7hy3qg1w7hy3qg1w7hy3q-x.drv";
+    auto elem = NixStringContextElem::parse(drvDeep);
+    auto * p = std::get_if<NixStringContextElem::DrvDeep>(&elem.raw);
+    ASSERT_TRUE(p);
+    ASSERT_EQ(p->drvPath, StorePath { drvDeep.substr(1) });
+    ASSERT_EQ(elem.to_string(), drvDeep);
+}
+
+/**
+ * Round trip (string <-> data structure) test for a simpler
+ * `NixStringContextElem::Built`.
+ */
+TEST(NixStringContextElemTest, built_opaque) {
+    std::string_view built = "!foo!g1w7hy3qg1w7hy3qg1w7hy3qg1w7hy3q-x.drv";
+    auto elem = NixStringContextElem::parse(built);
+    auto * p = std::get_if<NixStringContextElem::Built>(&elem.raw);
+    ASSERT_TRUE(p);
+    ASSERT_EQ(p->output, "foo");
+    ASSERT_EQ(*p->drvPath, ((SingleDerivedPath) SingleDerivedPath::Opaque {
+        .path = StorePath { built.substr(5) },
+    }));
+    ASSERT_EQ(elem.to_string(), built);
+}
+
+/**
+ * Round trip (string <-> data structure) test for a more complex,
+ * inductive `NixStringContextElem::Built`.
+ */
+TEST(NixStringContextElemTest, built_built) {
+    /**
+     * We set these in tests rather than the regular globals so we don't have
+     * to worry about race conditions if the tests run concurrently.
+     */
+    ExperimentalFeatureSettings mockXpSettings;
+    mockXpSettings.set("experimental-features", "dynamic-derivations ca-derivations");
+
+    std::string_view built = "!foo!bar!g1w7hy3qg1w7hy3qg1w7hy3qg1w7hy3q-x.drv";
+    auto elem = NixStringContextElem::parse(built, mockXpSettings);
+    auto * p = std::get_if<NixStringContextElem::Built>(&elem.raw);
+    ASSERT_TRUE(p);
+    ASSERT_EQ(p->output, "foo");
+    auto * drvPath = std::get_if<SingleDerivedPath::Built>(&*p->drvPath);
+    ASSERT_TRUE(drvPath);
+    ASSERT_EQ(drvPath->output, "bar");
+    ASSERT_EQ(*drvPath->drvPath, ((SingleDerivedPath) SingleDerivedPath::Opaque {
+        .path = StorePath { built.substr(9) },
+    }));
+    ASSERT_EQ(elem.to_string(), built);
+}
+
+/**
+ * Without the right experimental features enabled, we cannot parse a
+ * complex inductive string context element.
+ */
+TEST(NixStringContextElemTest, built_built_xp) {
+    ASSERT_THROW(
+        NixStringContextElem::parse("!foo!bar!g1w7hy3qg1w7hy3qg1w7hy3qg1w7hy3q-x.drv"),        MissingExperimentalFeature);
+}
+
+#ifndef COVERAGE
+
+RC_GTEST_PROP(
+    NixStringContextElemTest,
+    prop_round_rip,
+    (const NixStringContextElem & o))
+{
+    RC_ASSERT(o == NixStringContextElem::parse(o.to_string()));
+}
+
+#endif
+
+}

src/libexpr-tests/value/print.cc

@@ -0,0 +1,788 @@
+#include "tests/libexpr.hh"
+
+#include "value.hh"
+#include "print.hh"
+
+namespace nix {
+
+using namespace testing;
+
+struct ValuePrintingTests : LibExprTest
+{
+    template<class... A>
+    void test(Value v, std::string_view expected, A... args)
+    {
+        std::stringstream out;
+        v.print(state, out, args...);
+        ASSERT_EQ(out.str(), expected);
+    }
+};
+
+TEST_F(ValuePrintingTests, tInt)
+{
+    Value vInt;
+    vInt.mkInt(10);
+    test(vInt, "10");
+}
+
+TEST_F(ValuePrintingTests, tBool)
+{
+    Value vBool;
+    vBool.mkBool(true);
+    test(vBool, "true");
+}
+
+TEST_F(ValuePrintingTests, tString)
+{
+    Value vString;
+    vString.mkString("some-string");
+    test(vString, "\"some-string\"");
+}
+
+TEST_F(ValuePrintingTests, tPath)
+{
+    Value vPath;
+    vPath.mkString("/foo");
+    test(vPath, "\"/foo\"");
+}
+
+TEST_F(ValuePrintingTests, tNull)
+{
+    Value vNull;
+    vNull.mkNull();
+    test(vNull, "null");
+}
+
+TEST_F(ValuePrintingTests, tAttrs)
+{
+    Value vOne;
+    vOne.mkInt(1);
+
+    Value vTwo;
+    vTwo.mkInt(2);
+
+    BindingsBuilder builder(state, state.allocBindings(10));
+    builder.insert(state.symbols.create("one"), &vOne);
+    builder.insert(state.symbols.create("two"), &vTwo);
+
+    Value vAttrs;
+    vAttrs.mkAttrs(builder.finish());
+
+    test(vAttrs, "{ one = 1; two = 2; }");
+}
+
+TEST_F(ValuePrintingTests, tList)
+{
+    Value vOne;
+    vOne.mkInt(1);
+
+    Value vTwo;
+    vTwo.mkInt(2);
+
+    auto list = state.buildList(3);
+    list.elems[0] = &vOne;
+    list.elems[1] = &vTwo;
+    Value vList;
+    vList.mkList(list);
+
+    test(vList, "[ 1 2 «nullptr» ]");
+}
+
+TEST_F(ValuePrintingTests, vThunk)
+{
+    Value vThunk;
+    vThunk.mkThunk(nullptr, nullptr);
+
+    test(vThunk, "«thunk»");
+}
+
+TEST_F(ValuePrintingTests, vApp)
+{
+    Value vApp;
+    vApp.mkApp(nullptr, nullptr);
+
+    test(vApp, "«thunk»");
+}
+
+TEST_F(ValuePrintingTests, vLambda)
+{
+    Env env {
+        .up = nullptr,
+        .values = { }
+    };
+    PosTable::Origin origin = state.positions.addOrigin(std::monostate(), 1);
+    auto posIdx = state.positions.add(origin, 0);
+    auto body = ExprInt(0);
+    auto formals = Formals {};
+
+    ExprLambda eLambda(posIdx, createSymbol("a"), &formals, &body);
+
+    Value vLambda;
+    vLambda.mkLambda(&env, &eLambda);
+
+    test(vLambda, "«lambda @ «none»:1:1»");
+
+    eLambda.setName(createSymbol("puppy"));
+
+    test(vLambda, "«lambda puppy @ «none»:1:1»");
+}
+
+TEST_F(ValuePrintingTests, vPrimOp)
+{
+    Value vPrimOp;
+    PrimOp primOp{
+        .name = "puppy"
+    };
+    vPrimOp.mkPrimOp(&primOp);
+
+    test(vPrimOp, "«primop puppy»");
+}
+
+TEST_F(ValuePrintingTests, vPrimOpApp)
+{
+    PrimOp primOp{
+        .name = "puppy"
+    };
+    Value vPrimOp;
+    vPrimOp.mkPrimOp(&primOp);
+
+    Value vPrimOpApp;
+    vPrimOpApp.mkPrimOpApp(&vPrimOp, nullptr);
+
+    test(vPrimOpApp, "«partially applied primop puppy»");
+}
+
+TEST_F(ValuePrintingTests, vExternal)
+{
+    struct MyExternal : ExternalValueBase
+    {
+    public:
+        std::string showType() const override
+        {
+            return "";
+        }
+        std::string typeOf() const override
+        {
+            return "";
+        }
+        virtual std::ostream & print(std::ostream & str) const override
+        {
+            str << "testing-external!";
+            return str;
+        }
+    } myExternal;
+    Value vExternal;
+    vExternal.mkExternal(&myExternal);
+
+    test(vExternal, "testing-external!");
+}
+
+TEST_F(ValuePrintingTests, vFloat)
+{
+    Value vFloat;
+    vFloat.mkFloat(2.0);
+
+    test(vFloat, "2");
+}
+
+TEST_F(ValuePrintingTests, vBlackhole)
+{
+    Value vBlackhole;
+    vBlackhole.mkBlackhole();
+    test(vBlackhole, "«potential infinite recursion»");
+}
+
+TEST_F(ValuePrintingTests, depthAttrs)
+{
+    Value vOne;
+    vOne.mkInt(1);
+
+    Value vTwo;
+    vTwo.mkInt(2);
+
+    BindingsBuilder builderEmpty(state, state.allocBindings(0));
+    Value vAttrsEmpty;
+    vAttrsEmpty.mkAttrs(builderEmpty.finish());
+
+    BindingsBuilder builder(state, state.allocBindings(10));
+    builder.insert(state.symbols.create("one"), &vOne);
+    builder.insert(state.symbols.create("two"), &vTwo);
+    builder.insert(state.symbols.create("nested"), &vAttrsEmpty);
+
+    Value vAttrs;
+    vAttrs.mkAttrs(builder.finish());
+
+    BindingsBuilder builder2(state, state.allocBindings(10));
+    builder2.insert(state.symbols.create("one"), &vOne);
+    builder2.insert(state.symbols.create("two"), &vTwo);
+    builder2.insert(state.symbols.create("nested"), &vAttrs);
+
+    Value vNested;
+    vNested.mkAttrs(builder2.finish());
+
+    test(vNested, "{ nested = { ... }; one = 1; two = 2; }", PrintOptions { .maxDepth = 1 });
+    test(vNested, "{ nested = { nested = { ... }; one = 1; two = 2; }; one = 1; two = 2; }", PrintOptions { .maxDepth = 2 });
+    test(vNested, "{ nested = { nested = { }; one = 1; two = 2; }; one = 1; two = 2; }", PrintOptions { .maxDepth = 3 });
+    test(vNested, "{ nested = { nested = { }; one = 1; two = 2; }; one = 1; two = 2; }", PrintOptions { .maxDepth = 4 });
+}
+
+TEST_F(ValuePrintingTests, depthList)
+{
+    Value vOne;
+    vOne.mkInt(1);
+
+    Value vTwo;
+    vTwo.mkInt(2);
+
+    BindingsBuilder builder(state, state.allocBindings(10));
+    builder.insert(state.symbols.create("one"), &vOne);
+    builder.insert(state.symbols.create("two"), &vTwo);
+
+    Value vAttrs;
+    vAttrs.mkAttrs(builder.finish());
+
+    BindingsBuilder builder2(state, state.allocBindings(10));
+    builder2.insert(state.symbols.create("one"), &vOne);
+    builder2.insert(state.symbols.create("two"), &vTwo);
+    builder2.insert(state.symbols.create("nested"), &vAttrs);
+
+    Value vNested;
+    vNested.mkAttrs(builder2.finish());
+
+    auto list = state.buildList(3);
+    list.elems[0] = &vOne;
+    list.elems[1] = &vTwo;
+    list.elems[2] = &vNested;
+    Value vList;
+    vList.mkList(list);
+
+    test(vList, "[ 1 2 { ... } ]", PrintOptions { .maxDepth = 1 });
+    test(vList, "[ 1 2 { nested = { ... }; one = 1; two = 2; } ]", PrintOptions { .maxDepth = 2 });
+    test(vList, "[ 1 2 { nested = { one = 1; two = 2; }; one = 1; two = 2; } ]", PrintOptions { .maxDepth = 3 });
+    test(vList, "[ 1 2 { nested = { one = 1; two = 2; }; one = 1; two = 2; } ]", PrintOptions { .maxDepth = 4 });
+    test(vList, "[ 1 2 { nested = { one = 1; two = 2; }; one = 1; two = 2; } ]", PrintOptions { .maxDepth = 5 });
+}
+
+struct StringPrintingTests : LibExprTest
+{
+    template<class... A>
+    void test(std::string_view literal, std::string_view expected, unsigned int maxLength, A... args)
+    {
+        Value v;
+        v.mkString(literal);
+
+        std::stringstream out;
+        printValue(state, out, v, PrintOptions {
+            .maxStringLength = maxLength
+        });
+        ASSERT_EQ(out.str(), expected);
+    }
+};
+
+TEST_F(StringPrintingTests, maxLengthTruncation)
+{
+    test("abcdefghi", "\"abcdefghi\"", 10);
+    test("abcdefghij", "\"abcdefghij\"", 10);
+    test("abcdefghijk", "\"abcdefghij\" «1 byte elided»", 10);
+    test("abcdefghijkl", "\"abcdefghij\" «2 bytes elided»", 10);
+    test("abcdefghijklm", "\"abcdefghij\" «3 bytes elided»", 10);
+}
+
+// Check that printing an attrset shows 'important' attributes like `type`
+// first, but only reorder the attrs when we have a maxAttrs budget.
+TEST_F(ValuePrintingTests, attrsTypeFirst)
+{
+    Value vType;
+    vType.mkString("puppy");
+
+    Value vApple;
+    vApple.mkString("apple");
+
+    BindingsBuilder builder(state, state.allocBindings(10));
+    builder.insert(state.symbols.create("type"), &vType);
+    builder.insert(state.symbols.create("apple"), &vApple);
+
+    Value vAttrs;
+    vAttrs.mkAttrs(builder.finish());
+
+    test(vAttrs,
+         "{ type = \"puppy\"; apple = \"apple\"; }",
+         PrintOptions {
+            .maxAttrs = 100
+         });
+
+    test(vAttrs,
+         "{ apple = \"apple\"; type = \"puppy\"; }",
+         PrintOptions { });
+}
+
+TEST_F(ValuePrintingTests, ansiColorsInt)
+{
+    Value v;
+    v.mkInt(10);
+
+    test(v,
+         ANSI_CYAN "10" ANSI_NORMAL,
+         PrintOptions {
+             .ansiColors = true
+         });
+}
+
+TEST_F(ValuePrintingTests, ansiColorsFloat)
+{
+    Value v;
+    v.mkFloat(1.6);
+
+    test(v,
+         ANSI_CYAN "1.6" ANSI_NORMAL,
+         PrintOptions {
+             .ansiColors = true
+         });
+}
+
+TEST_F(ValuePrintingTests, ansiColorsBool)
+{
+    Value v;
+    v.mkBool(true);
+
+    test(v,
+         ANSI_CYAN "true" ANSI_NORMAL,
+         PrintOptions {
+             .ansiColors = true
+         });
+}
+
+TEST_F(ValuePrintingTests, ansiColorsString)
+{
+    Value v;
+    v.mkString("puppy");
+
+    test(v,
+         ANSI_MAGENTA "\"puppy\"" ANSI_NORMAL,
+         PrintOptions {
+             .ansiColors = true
+        });
+}
+
+TEST_F(ValuePrintingTests, ansiColorsStringElided)
+{
+    Value v;
+    v.mkString("puppy");
+
+    test(v,
+         ANSI_MAGENTA "\"pup\" " ANSI_FAINT "«2 bytes elided»" ANSI_NORMAL,
+         PrintOptions {
+             .ansiColors = true,
+             .maxStringLength = 3
+         });
+}
+
+TEST_F(ValuePrintingTests, ansiColorsPath)
+{
+    Value v;
+    v.mkPath(state.rootPath(CanonPath("puppy")));
+
+    test(v,
+         ANSI_GREEN "/puppy" ANSI_NORMAL,
+         PrintOptions {
+             .ansiColors = true
+         });
+}
+
+TEST_F(ValuePrintingTests, ansiColorsNull)
+{
+    Value v;
+    v.mkNull();
+
+    test(v,
+         ANSI_CYAN "null" ANSI_NORMAL,
+         PrintOptions {
+             .ansiColors = true
+         });
+}
+
+TEST_F(ValuePrintingTests, ansiColorsAttrs)
+{
+    Value vOne;
+    vOne.mkInt(1);
+
+    Value vTwo;
+    vTwo.mkInt(2);
+
+    BindingsBuilder builder(state, state.allocBindings(10));
+    builder.insert(state.symbols.create("one"), &vOne);
+    builder.insert(state.symbols.create("two"), &vTwo);
+
+    Value vAttrs;
+    vAttrs.mkAttrs(builder.finish());
+
+    test(vAttrs,
+         "{ one = " ANSI_CYAN "1" ANSI_NORMAL "; two = " ANSI_CYAN "2" ANSI_NORMAL "; }",
+         PrintOptions {
+             .ansiColors = true
+         });
+}
+
+TEST_F(ValuePrintingTests, ansiColorsDerivation)
+{
+    Value vDerivation;
+    vDerivation.mkString("derivation");
+
+    BindingsBuilder builder(state, state.allocBindings(10));
+    builder.insert(state.sType, &vDerivation);
+
+    Value vAttrs;
+    vAttrs.mkAttrs(builder.finish());
+
+    test(vAttrs,
+         ANSI_GREEN "«derivation»" ANSI_NORMAL,
+         PrintOptions {
+             .ansiColors = true,
+             .force = true,
+             .derivationPaths = true
+         });
+
+    test(vAttrs,
+         "{ type = " ANSI_MAGENTA "\"derivation\"" ANSI_NORMAL "; }",
+         PrintOptions {
+             .ansiColors = true,
+             .force = true
+         });
+}
+
+TEST_F(ValuePrintingTests, ansiColorsError)
+{
+    Value throw_ = state.getBuiltin("throw");
+    Value message;
+    message.mkString("uh oh!");
+    Value vError;
+    vError.mkApp(&throw_, &message);
+
+    test(vError,
+         ANSI_RED
+         "«error: uh oh!»"
+         ANSI_NORMAL,
+         PrintOptions {
+             .ansiColors = true,
+             .force = true,
+         });
+}
+
+TEST_F(ValuePrintingTests, ansiColorsDerivationError)
+{
+    Value throw_ = state.getBuiltin("throw");
+    Value message;
+    message.mkString("uh oh!");
+    Value vError;
+    vError.mkApp(&throw_, &message);
+
+    Value vDerivation;
+    vDerivation.mkString("derivation");
+
+    BindingsBuilder builder(state, state.allocBindings(10));
+    builder.insert(state.sType, &vDerivation);
+    builder.insert(state.sDrvPath, &vError);
+
+    Value vAttrs;
+    vAttrs.mkAttrs(builder.finish());
+
+    test(vAttrs,
+         "{ drvPath = "
+         ANSI_RED
+         "«error: uh oh!»"
+         ANSI_NORMAL
+         "; type = "
+         ANSI_MAGENTA
+         "\"derivation\""
+         ANSI_NORMAL
+         "; }",
+         PrintOptions {
+             .ansiColors = true,
+             .force = true
+         });
+
+    test(vAttrs,
+         ANSI_RED
+         "«error: uh oh!»"
+         ANSI_NORMAL,
+         PrintOptions {
+             .ansiColors = true,
+             .force = true,
+             .derivationPaths = true,
+         });
+}
+
+TEST_F(ValuePrintingTests, ansiColorsAssert)
+{
+    ExprVar eFalse(state.symbols.create("false"));
+    eFalse.bindVars(state, state.staticBaseEnv);
+    ExprInt eInt(1);
+
+    ExprAssert expr(noPos, &eFalse, &eInt);
+
+    Value v;
+    state.mkThunk_(v, &expr);
+
+    test(v,
+         ANSI_RED "«error: assertion 'false' failed»" ANSI_NORMAL,
+         PrintOptions {
+             .ansiColors = true,
+             .force = true
+         });
+}
+
+TEST_F(ValuePrintingTests, ansiColorsList)
+{
+    Value vOne;
+    vOne.mkInt(1);
+
+    Value vTwo;
+    vTwo.mkInt(2);
+
+    auto list = state.buildList(3);
+    list.elems[0] = &vOne;
+    list.elems[1] = &vTwo;
+    Value vList;
+    vList.mkList(list);
+
+    test(vList,
+         "[ " ANSI_CYAN "1" ANSI_NORMAL " " ANSI_CYAN "2" ANSI_NORMAL " " ANSI_MAGENTA "«nullptr»" ANSI_NORMAL " ]",
+         PrintOptions {
+             .ansiColors = true
+         });
+}
+
+TEST_F(ValuePrintingTests, ansiColorsLambda)
+{
+    Env env {
+        .up = nullptr,
+        .values = { }
+    };
+    PosTable::Origin origin = state.positions.addOrigin(std::monostate(), 1);
+    auto posIdx = state.positions.add(origin, 0);
+    auto body = ExprInt(0);
+    auto formals = Formals {};
+
+    ExprLambda eLambda(posIdx, createSymbol("a"), &formals, &body);
+
+    Value vLambda;
+    vLambda.mkLambda(&env, &eLambda);
+
+    test(vLambda,
+         ANSI_BLUE "«lambda @ «none»:1:1»" ANSI_NORMAL,
+         PrintOptions {
+             .ansiColors = true,
+             .force = true
+         });
+
+    eLambda.setName(createSymbol("puppy"));
+
+    test(vLambda,
+         ANSI_BLUE "«lambda puppy @ «none»:1:1»" ANSI_NORMAL,
+         PrintOptions {
+             .ansiColors = true,
+             .force = true
+         });
+}
+
+TEST_F(ValuePrintingTests, ansiColorsPrimOp)
+{
+    PrimOp primOp{
+        .name = "puppy"
+    };
+    Value v;
+    v.mkPrimOp(&primOp);
+
+    test(v,
+         ANSI_BLUE "«primop puppy»" ANSI_NORMAL,
+         PrintOptions {
+             .ansiColors = true
+         });
+}
+
+TEST_F(ValuePrintingTests, ansiColorsPrimOpApp)
+{
+    PrimOp primOp{
+        .name = "puppy"
+    };
+    Value vPrimOp;
+    vPrimOp.mkPrimOp(&primOp);
+
+    Value v;
+    v.mkPrimOpApp(&vPrimOp, nullptr);
+
+    test(v,
+         ANSI_BLUE "«partially applied primop puppy»" ANSI_NORMAL,
+         PrintOptions {
+             .ansiColors = true
+         });
+}
+
+TEST_F(ValuePrintingTests, ansiColorsThunk)
+{
+    Value v;
+    v.mkThunk(nullptr, nullptr);
+
+    test(v,
+         ANSI_MAGENTA "«thunk»" ANSI_NORMAL,
+         PrintOptions {
+             .ansiColors = true
+         });
+}
+
+TEST_F(ValuePrintingTests, ansiColorsBlackhole)
+{
+    Value v;
+    v.mkBlackhole();
+
+    test(v,
+         ANSI_RED "«potential infinite recursion»" ANSI_NORMAL,
+         PrintOptions {
+             .ansiColors = true
+         });
+}
+
+TEST_F(ValuePrintingTests, ansiColorsAttrsRepeated)
+{
+    BindingsBuilder emptyBuilder(state, state.allocBindings(1));
+
+    Value vEmpty;
+    vEmpty.mkAttrs(emptyBuilder.finish());
+
+    BindingsBuilder builder(state, state.allocBindings(10));
+    builder.insert(state.symbols.create("a"), &vEmpty);
+    builder.insert(state.symbols.create("b"), &vEmpty);
+
+    Value vAttrs;
+    vAttrs.mkAttrs(builder.finish());
+
+    test(vAttrs,
+         "{ a = { }; b = " ANSI_MAGENTA "«repeated»" ANSI_NORMAL "; }",
+         PrintOptions {
+             .ansiColors = true
+         });
+}
+
+TEST_F(ValuePrintingTests, ansiColorsListRepeated)
+{
+    BindingsBuilder emptyBuilder(state, state.allocBindings(1));
+
+    Value vEmpty;
+    vEmpty.mkAttrs(emptyBuilder.finish());
+
+    auto list = state.buildList(2);
+    list.elems[0] = &vEmpty;
+    list.elems[1] = &vEmpty;
+    Value vList;
+    vList.mkList(list);
+
+    test(vList,
+         "[ { } " ANSI_MAGENTA "«repeated»" ANSI_NORMAL " ]",
+         PrintOptions {
+             .ansiColors = true
+         });
+}
+
+TEST_F(ValuePrintingTests, listRepeated)
+{
+    BindingsBuilder emptyBuilder(state, state.allocBindings(1));
+
+    Value vEmpty;
+    vEmpty.mkAttrs(emptyBuilder.finish());
+
+    auto list = state.buildList(2);
+    list.elems[0] = &vEmpty;
+    list.elems[1] = &vEmpty;
+    Value vList;
+    vList.mkList(list);
+
+    test(vList, "[ { } «repeated» ]", PrintOptions { });
+    test(vList,
+         "[ { } { } ]",
+         PrintOptions {
+             .trackRepeated = false
+         });
+}
+
+TEST_F(ValuePrintingTests, ansiColorsAttrsElided)
+{
+    Value vOne;
+    vOne.mkInt(1);
+
+    Value vTwo;
+    vTwo.mkInt(2);
+
+    BindingsBuilder builder(state, state.allocBindings(10));
+    builder.insert(state.symbols.create("one"), &vOne);
+    builder.insert(state.symbols.create("two"), &vTwo);
+
+    Value vAttrs;
+    vAttrs.mkAttrs(builder.finish());
+
+    test(vAttrs,
+         "{ one = " ANSI_CYAN "1" ANSI_NORMAL "; " ANSI_FAINT "«1 attribute elided»" ANSI_NORMAL " }",
+         PrintOptions {
+             .ansiColors = true,
+             .maxAttrs = 1
+         });
+
+    Value vThree;
+    vThree.mkInt(3);
+
+    builder.insert(state.symbols.create("three"), &vThree);
+    vAttrs.mkAttrs(builder.finish());
+
+    test(vAttrs,
+         "{ one = " ANSI_CYAN "1" ANSI_NORMAL "; " ANSI_FAINT "«2 attributes elided»" ANSI_NORMAL " }",
+         PrintOptions {
+             .ansiColors = true,
+             .maxAttrs = 1
+         });
+}
+
+TEST_F(ValuePrintingTests, ansiColorsListElided)
+{
+    BindingsBuilder emptyBuilder(state, state.allocBindings(1));
+
+    Value vOne;
+    vOne.mkInt(1);
+
+    Value vTwo;
+    vTwo.mkInt(2);
+
+    {
+    auto list = state.buildList(2);
+    list.elems[0] = &vOne;
+    list.elems[1] = &vTwo;
+    Value vList;
+    vList.mkList(list);
+
+    test(vList,
+         "[ " ANSI_CYAN "1" ANSI_NORMAL " " ANSI_FAINT "«1 item elided»" ANSI_NORMAL " ]",
+         PrintOptions {
+             .ansiColors = true,
+             .maxListItems = 1
+         });
+    }
+
+    Value vThree;
+    vThree.mkInt(3);
+
+    {
+    auto list = state.buildList(3);
+    list.elems[0] = &vOne;
+    list.elems[1] = &vTwo;
+    list.elems[2] = &vThree;
+    Value vList;
+    vList.mkList(list);
+
+    test(vList,
+         "[ " ANSI_CYAN "1" ANSI_NORMAL " " ANSI_FAINT "«2 items elided»" ANSI_NORMAL " ]",
+         PrintOptions {
+             .ansiColors = true,
+             .maxListItems = 1
+         });
+    }
+}
+
+} // namespace nix

src/libexpr-tests/value/value.cc

@@ -0,0 +1,25 @@
+#include "value.hh"
+
+#include "tests/libstore.hh"
+
+namespace nix {
+
+class ValueTest : public LibStoreTest
+{};
+
+TEST_F(ValueTest, unsetValue)
+{
+    Value unsetValue;
+    ASSERT_EQ(false, unsetValue.isValid());
+    ASSERT_EQ(nThunk, unsetValue.type(true));
+    ASSERT_DEATH(unsetValue.type(), "");
+}
+
+TEST_F(ValueTest, vInt)
+{
+    Value vInt;
+    vInt.mkInt(42);
+    ASSERT_EQ(true, vInt.isValid());
+}
+
+} // namespace nix

src/libexpr/primops.cc

@@ -178,6 +178,78 @@ static void mkOutputString(
         o.second.path(*state.store, Derivation::nameFromPath(drvPath), o.first));
 }
 
+/**
+ * `import` will parse a derivation when it imports a `.drv` file from the store.
+ *
+ * @param state The evaluation state.
+ * @param pos The position of the `import` call.
+ * @param path The path to the `.drv` to import.
+ * @param storePath The path to the `.drv` to import.
+ * @param v Return value
+ */
+void derivationToValue(EvalState & state, const PosIdx pos, const SourcePath & path, const StorePath & storePath, Value & v) {
+    auto path2 = path.path.abs();
+    Derivation drv = state.store->readDerivation(storePath);
+    auto attrs = state.buildBindings(3 + drv.outputs.size());
+    attrs.alloc(state.sDrvPath).mkString(path2, {
+        NixStringContextElem::DrvDeep { .drvPath = storePath },
+    });
+    attrs.alloc(state.sName).mkString(drv.env["name"]);
+
+    auto list = state.buildList(drv.outputs.size());
+    for (const auto & [i, o] : enumerate(drv.outputs)) {
+        mkOutputString(state, attrs, storePath, o);
+        (list[i] = state.allocValue())->mkString(o.first);
+    }
+    attrs.alloc(state.sOutputs).mkList(list);
+
+    auto w = state.allocValue();
+    w->mkAttrs(attrs);
+
+    if (!state.vImportedDrvToDerivation) {
+        state.vImportedDrvToDerivation = allocRootValue(state.allocValue());
+        state.eval(state.parseExprFromString(
+            #include "imported-drv-to-derivation.nix.gen.hh"
+            , state.rootPath(CanonPath::root)), **state.vImportedDrvToDerivation);
+    }
+
+    state.forceFunction(**state.vImportedDrvToDerivation, pos, "while evaluating imported-drv-to-derivation.nix.gen.hh");
+    v.mkApp(*state.vImportedDrvToDerivation, w);
+    state.forceAttrs(v, pos, "while calling imported-drv-to-derivation.nix.gen.hh");
+}
+
+/**
+ * Import a Nix file with an alternate base scope, as `builtins.scopedImport` does.
+ *
+ * @param state The evaluation state.
+ * @param pos The position of the import call.
+ * @param path The path to the file to import.
+ * @param vScope The base scope to use for the import.
+ * @param v Return value
+ */
+static void scopedImport(EvalState & state, const PosIdx pos, SourcePath & path, Value * vScope, Value & v) {
+    state.forceAttrs(*vScope, pos, "while evaluating the first argument passed to builtins.scopedImport");
+
+    Env * env = &state.allocEnv(vScope->attrs()->size());
+    env->up = &state.baseEnv;
+
+    auto staticEnv = std::make_shared<StaticEnv>(nullptr, state.staticBaseEnv.get(), vScope->attrs()->size());
+
+    unsigned int displ = 0;
+    for (auto & attr : *vScope->attrs()) {
+        staticEnv->vars.emplace_back(attr.name, displ);
+        env->values[displ++] = attr.value;
+    }
+
+    // No need to call staticEnv.sort(), because
+    // args[0]->attrs is already sorted.
+
+    printTalkative("evaluating file '%1%'", path);
+    Expr * e = state.parseExprFromFile(resolveExprPath(path), staticEnv);
+
+    e->eval(state, *env, v);
+}
+
 /* Load and evaluate an expression from path specified by the
    argument. */
 static void import(EvalState & state, const PosIdx pos, Value & vPath, Value * vScope, Value & v)
@@ -196,60 +268,13 @@ static void import(EvalState & state, const PosIdx pos, Value & vPath, Value * v
     };
 
     if (auto storePath = isValidDerivationInStore()) {
-        Derivation drv = state.store->readDerivation(*storePath);
-        auto attrs = state.buildBindings(3 + drv.outputs.size());
-        attrs.alloc(state.sDrvPath).mkString(path2, {
-            NixStringContextElem::DrvDeep { .drvPath = *storePath },
-        });
-        attrs.alloc(state.sName).mkString(drv.env["name"]);
-
-        auto list = state.buildList(drv.outputs.size());
-        for (const auto & [i, o] : enumerate(drv.outputs)) {
-            mkOutputString(state, attrs, *storePath, o);
-            (list[i] = state.allocValue())->mkString(o.first);
-        }
-        attrs.alloc(state.sOutputs).mkList(list);
-
-        auto w = state.allocValue();
-        w->mkAttrs(attrs);
-
-        if (!state.vImportedDrvToDerivation) {
-            state.vImportedDrvToDerivation = allocRootValue(state.allocValue());
-            state.eval(state.parseExprFromString(
-                #include "imported-drv-to-derivation.nix.gen.hh"
-                , state.rootPath(CanonPath::root)), **state.vImportedDrvToDerivation);
-        }
-
-        state.forceFunction(**state.vImportedDrvToDerivation, pos, "while evaluating imported-drv-to-derivation.nix.gen.hh");
-        v.mkApp(*state.vImportedDrvToDerivation, w);
-        state.forceAttrs(v, pos, "while calling imported-drv-to-derivation.nix.gen.hh");
+        derivationToValue(state, pos, path, *storePath, v);
+    }
+    else if (vScope) {
+        scopedImport(state, pos, path, vScope, v);
     }
-
     else {
-        if (!vScope)
-            state.evalFile(path, v);
-        else {
-            state.forceAttrs(*vScope, pos, "while evaluating the first argument passed to builtins.scopedImport");
-
-            Env * env = &state.allocEnv(vScope->attrs()->size());
-            env->up = &state.baseEnv;
-
-            auto staticEnv = std::make_shared<StaticEnv>(nullptr, state.staticBaseEnv.get(), vScope->attrs()->size());
-
-            unsigned int displ = 0;
-            for (auto & attr : *vScope->attrs()) {
-                staticEnv->vars.emplace_back(attr.name, displ);
-                env->values[displ++] = attr.value;
-            }
-
-            // No need to call staticEnv.sort(), because
-            // args[0]->attrs is already sorted.
-
-            printTalkative("evaluating file '%1%'", path);
-            Expr * e = state.parseExprFromFile(resolveExprPath(path), staticEnv);
-
-            e->eval(state, *env, v);
-        }
+        state.evalFile(path, v);
     }
 }
 
@@ -944,6 +969,9 @@ static RegisterPrimOp primop_tryEval({
       `let e = { x = throw ""; }; in
       (builtins.tryEval (builtins.deepSeq e e)).success` will be
       `false`.
+
+      `tryEval` intentionally does not return the error message, because that risks bringing non-determinism into the evaluation result, and it would become very difficult to improve error reporting without breaking existing expressions.
+      Instead, use [`builtins.addErrorContext`](@docroot@/language/builtins.md#builtins-addErrorContext) to add context to the error message, and use a Nix unit testing tool for testing.
     )",
     .fun = prim_tryEval,
 });

src/libfetchers-tests/.version

@@ -0,0 +1 @@
+../../.version

src/libfetchers-tests/build-utils-meson

@@ -0,0 +1 @@
+../../build-utils-meson

src/libfetchers-tests/data/public-key/defaultType.json

@@ -0,0 +1,4 @@
+{
+  "key": "ABCDE",
+  "type": "ssh-ed25519"
+}

src/libfetchers-tests/data/public-key/noRoundTrip.json

@@ -0,0 +1,3 @@
+{
+  "key": "ABCDE"
+}

src/libfetchers-tests/data/public-key/simple.json

@@ -0,0 +1,4 @@
+{
+  "key": "ABCDE",
+  "type": "ssh-rsa"
+}

src/libfetchers-tests/git-utils.cc

@@ -0,0 +1,112 @@
+#include "git-utils.hh"
+#include "file-system.hh"
+#include "gmock/gmock.h"
+#include <git2/global.h>
+#include <git2/repository.h>
+#include <git2/types.h>
+#include <gtest/gtest.h>
+#include "fs-sink.hh"
+#include "serialise.hh"
+
+namespace nix {
+
+class GitUtilsTest : public ::testing::Test
+{
+    // We use a single repository for all tests.
+    Path tmpDir;
+    std::unique_ptr<AutoDelete> delTmpDir;
+
+public:
+    void SetUp() override
+    {
+        tmpDir = createTempDir();
+        delTmpDir = std::make_unique<AutoDelete>(tmpDir, true);
+
+        // Create the repo with libgit2
+        git_libgit2_init();
+        git_repository * repo = nullptr;
+        auto r = git_repository_init(&repo, tmpDir.c_str(), 0);
+        ASSERT_EQ(r, 0);
+        git_repository_free(repo);
+    }
+
+    void TearDown() override
+    {
+        // Destroy the AutoDelete, triggering removal
+        // not AutoDelete::reset(), which would cancel the deletion.
+        delTmpDir.reset();
+    }
+
+    ref<GitRepo> openRepo()
+    {
+        return GitRepo::openRepo(tmpDir, true, false);
+    }
+};
+
+void writeString(CreateRegularFileSink & fileSink, std::string contents, bool executable)
+{
+    if (executable)
+        fileSink.isExecutable();
+    fileSink.preallocateContents(contents.size());
+    fileSink(contents);
+}
+
+TEST_F(GitUtilsTest, sink_basic)
+{
+    auto repo = openRepo();
+    auto sink = repo->getFileSystemObjectSink();
+
+    // TODO/Question: It seems a little odd that we use the tarball-like convention of requiring a top-level directory
+    // here
+    //                The sync method does not document this behavior, should probably renamed because it's not very
+    //                general, and I can't imagine that "non-conventional" archives or any other source to be handled by
+    //                this sink.
+
+    sink->createDirectory(CanonPath("foo-1.1"));
+
+    sink->createRegularFile(CanonPath("foo-1.1/hello"), [](CreateRegularFileSink & fileSink) {
+        writeString(fileSink, "hello world", false);
+    });
+    sink->createRegularFile(CanonPath("foo-1.1/bye"), [](CreateRegularFileSink & fileSink) {
+        writeString(fileSink, "thanks for all the fish", false);
+    });
+    sink->createSymlink(CanonPath("foo-1.1/bye-link"), "bye");
+    sink->createDirectory(CanonPath("foo-1.1/empty"));
+    sink->createDirectory(CanonPath("foo-1.1/links"));
+    sink->createHardlink(CanonPath("foo-1.1/links/foo"), CanonPath("foo-1.1/hello"));
+
+    // sink->createHardlink("foo-1.1/links/foo-2", CanonPath("foo-1.1/hello"));
+
+    auto result = repo->dereferenceSingletonDirectory(sink->flush());
+    auto accessor = repo->getAccessor(result, false);
+    auto entries = accessor->readDirectory(CanonPath::root);
+    ASSERT_EQ(entries.size(), 5);
+    ASSERT_EQ(accessor->readFile(CanonPath("hello")), "hello world");
+    ASSERT_EQ(accessor->readFile(CanonPath("bye")), "thanks for all the fish");
+    ASSERT_EQ(accessor->readLink(CanonPath("bye-link")), "bye");
+    ASSERT_EQ(accessor->readDirectory(CanonPath("empty")).size(), 0);
+    ASSERT_EQ(accessor->readFile(CanonPath("links/foo")), "hello world");
+};
+
+TEST_F(GitUtilsTest, sink_hardlink)
+{
+    auto repo = openRepo();
+    auto sink = repo->getFileSystemObjectSink();
+
+    sink->createDirectory(CanonPath("foo-1.1"));
+
+    sink->createRegularFile(CanonPath("foo-1.1/hello"), [](CreateRegularFileSink & fileSink) {
+        writeString(fileSink, "hello world", false);
+    });
+
+    try {
+        sink->createHardlink(CanonPath("foo-1.1/link"), CanonPath("hello"));
+        FAIL() << "Expected an exception";
+    } catch (const nix::Error & e) {
+        ASSERT_THAT(e.msg(), testing::HasSubstr("cannot find hard link target"));
+        ASSERT_THAT(e.msg(), testing::HasSubstr("/hello"));
+        ASSERT_THAT(e.msg(), testing::HasSubstr("foo-1.1/link"));
+    }
+};
+
+} // namespace nix

src/libfetchers-tests/local.mk

@@ -0,0 +1,37 @@
+check: libfetchers-tests_RUN
+
+programs += libfetchers-tests
+
+libfetchers-tests_NAME = libnixfetchers-tests
+
+libfetchers-tests_ENV := _NIX_TEST_UNIT_DATA=$(d)/data GTEST_OUTPUT=xml:$$testresults/libfetchers-tests.xml
+
+libfetchers-tests_DIR := $(d)
+
+ifeq ($(INSTALL_UNIT_TESTS), yes)
+  libfetchers-tests_INSTALL_DIR := $(checkbindir)
+else
+  libfetchers-tests_INSTALL_DIR :=
+endif
+
+libfetchers-tests_SOURCES := $(wildcard $(d)/*.cc)
+
+libfetchers-tests_EXTRA_INCLUDES = \
+    -I src/libstore-test-support \
+    -I src/libutil-test-support \
+    $(INCLUDE_libfetchers) \
+    $(INCLUDE_libstore) \
+    $(INCLUDE_libutil)
+
+libfetchers-tests_CXXFLAGS += $(libfetchers-tests_EXTRA_INCLUDES)
+
+libfetchers-tests_LIBS = \
+    libstore-test-support libutil-test-support \
+    libfetchers libstore libutil
+
+libfetchers-tests_LDFLAGS := -lrapidcheck $(GTEST_LIBS) $(LIBGIT2_LIBS)
+
+ifdef HOST_WINDOWS
+  # Increase the default reserved stack size to 65 MB so Nix doesn't run out of space
+  libfetchers-tests_LDFLAGS += -Wl,--stack,$(shell echo $$((65 * 1024 * 1024)))
+endif

src/libfetchers-tests/meson.build

@@ -0,0 +1,73 @@
+project('nix-fetchers-tests', 'cpp',
+  version : files('.version'),
+  default_options : [
+    'cpp_std=c++2a',
+    # TODO(Qyriad): increase the warning level
+    'warning_level=1',
+    'debug=true',
+    'optimization=2',
+    'errorlogs=true', # Please print logs for tests that fail
+  ],
+  meson_version : '>= 1.1',
+  license : 'LGPL-2.1-or-later',
+)
+
+cxx = meson.get_compiler('cpp')
+
+subdir('build-utils-meson/deps-lists')
+
+deps_private_maybe_subproject = [
+  dependency('nix-store-test-support'),
+  dependency('nix-fetchers'),
+]
+deps_public_maybe_subproject = [
+]
+subdir('build-utils-meson/subprojects')
+
+subdir('build-utils-meson/threads')
+
+subdir('build-utils-meson/export-all-symbols')
+
+rapidcheck = dependency('rapidcheck')
+deps_private += rapidcheck
+
+gtest = dependency('gtest', main : true)
+deps_private += gtest
+
+add_project_arguments(
+  # TODO(Qyriad): Yes this is how the autoconf+Make system did it.
+  # It would be nice for our headers to be idempotent instead.
+  '-include', 'config-util.hh',
+  '-include', 'config-store.hh',
+  # '-include', 'config-fetchers.h',
+  language : 'cpp',
+)
+
+subdir('build-utils-meson/diagnostics')
+
+sources = files(
+  'public-key.cc',
+)
+
+include_dirs = [include_directories('.')]
+
+
+this_exe = executable(
+  meson.project_name(),
+  sources,
+  dependencies : deps_private_subproject + deps_private + deps_other,
+  include_directories : include_dirs,
+  # TODO: -lrapidcheck, see ../libutil-support/build.meson
+  link_args: linker_export_flags + ['-lrapidcheck'],
+  # get main from gtest
+  install : true,
+)
+
+test(
+  meson.project_name(),
+  this_exe,
+  env : {
+    '_NIX_TEST_UNIT_DATA': meson.current_source_dir() / 'data',
+  },
+  protocol : 'gtest',
+)

src/libfetchers-tests/package.nix

@@ -0,0 +1,81 @@
+{ lib
+, buildPackages
+, stdenv
+, mkMesonExecutable
+
+, nix-fetchers
+, nix-store-test-support
+
+, rapidcheck
+, gtest
+, runCommand
+
+# Configuration Options
+
+, version
+, resolvePath
+}:
+
+let
+  inherit (lib) fileset;
+in
+
+mkMesonExecutable (finalAttrs: {
+  pname = "nix-fetchers-tests";
+  inherit version;
+
+  workDir = ./.;
+  fileset = fileset.unions [
+    ../../build-utils-meson
+    ./build-utils-meson
+    ../../.version
+    ./.version
+    ./meson.build
+    # ./meson.options
+    (fileset.fileFilter (file: file.hasExt "cc") ./.)
+    (fileset.fileFilter (file: file.hasExt "hh") ./.)
+  ];
+
+  buildInputs = [
+    nix-fetchers
+    nix-store-test-support
+    rapidcheck
+    gtest
+  ];
+
+  preConfigure =
+    # "Inline" .version so it's not a symlink, and includes the suffix.
+    # Do the meson utils, without modification.
+    ''
+      chmod u+w ./.version
+      echo ${version} > ../../.version
+    '';
+
+  mesonFlags = [
+  ];
+
+  env = lib.optionalAttrs (stdenv.isLinux && !(stdenv.hostPlatform.isStatic && stdenv.system == "aarch64-linux")) {
+    LDFLAGS = "-fuse-ld=gold";
+  };
+
+  passthru = {
+    tests = {
+      run = runCommand "${finalAttrs.pname}-run" {
+        meta.broken = !stdenv.hostPlatform.emulatorAvailable buildPackages;
+      } (lib.optionalString stdenv.hostPlatform.isWindows ''
+        export HOME="$PWD/home-dir"
+        mkdir -p "$HOME"
+      '' + ''
+        export _NIX_TEST_UNIT_DATA=${resolvePath ./data}
+        ${stdenv.hostPlatform.emulator buildPackages} ${lib.getExe finalAttrs.finalPackage}
+        touch $out
+      '');
+    };
+  };
+
+  meta = {
+    platforms = lib.platforms.unix ++ lib.platforms.windows;
+    mainProgram = finalAttrs.pname + stdenv.hostPlatform.extensions.executable;
+  };
+
+})

src/libfetchers-tests/public-key.cc

@@ -0,0 +1,54 @@
+#include <gtest/gtest.h>
+#include "fetchers.hh"
+#include "json-utils.hh"
+#include <nlohmann/json.hpp>
+#include "tests/characterization.hh"
+
+namespace nix {
+
+using nlohmann::json;
+
+class PublicKeyTest : public CharacterizationTest
+{
+    std::filesystem::path unitTestData = getUnitTestData() / "public-key";
+
+public:
+    std::filesystem::path goldenMaster(std::string_view testStem) const override {
+        return unitTestData / testStem;
+    }
+};
+
+#define TEST_JSON(FIXTURE, NAME, VAL)                                     \
+    TEST_F(FIXTURE, PublicKey_ ## NAME ## _from_json) {                   \
+        readTest(#NAME ".json", [&](const auto & encoded_) {              \
+            fetchers::PublicKey expected { VAL };                         \
+            fetchers::PublicKey got = nlohmann::json::parse(encoded_);    \
+            ASSERT_EQ(got, expected);                                     \
+        });                                                               \
+    }                                                                     \
+                                                                          \
+    TEST_F(FIXTURE, PublicKey_ ## NAME ## _to_json) {                     \
+        writeTest(#NAME ".json", [&]() -> json {                          \
+            return nlohmann::json(fetchers::PublicKey { VAL });           \
+        }, [](const auto & file) {                                        \
+            return json::parse(readFile(file));                           \
+        }, [](const auto & file, const auto & got) {                      \
+            return writeFile(file, got.dump(2) + "\n");                   \
+        });                                                               \
+    }
+
+TEST_JSON(PublicKeyTest, simple, (fetchers::PublicKey { .type = "ssh-rsa", .key = "ABCDE" }))
+
+TEST_JSON(PublicKeyTest, defaultType, fetchers::PublicKey { .key = "ABCDE" })
+
+#undef TEST_JSON
+
+TEST_F(PublicKeyTest, PublicKey_noRoundTrip_from_json) {
+    readTest("noRoundTrip.json", [&](const auto & encoded_) {
+        fetchers::PublicKey expected = { .type = "ssh-ed25519", .key = "ABCDE" };
+        fetchers::PublicKey got = nlohmann::json::parse(encoded_);
+        ASSERT_EQ(got, expected);
+    });
+}
+
+}

src/libfetchers/path.cc

@@ -158,7 +158,11 @@ struct PathInputScheme : InputScheme
             });
             storePath = store->addToStoreFromDump(*src, "source");
         }
-        input.attrs.insert_or_assign("lastModified", uint64_t(mtime));
+
+        /* Trust the lastModified value supplied by the user, if
+           any. It's not a "secure" attribute so we don't care. */
+        if (!input.getLastModified())
+            input.attrs.insert_or_assign("lastModified", uint64_t(mtime));
 
         return {makeStorePathAccessor(store, *storePath), std::move(input)};
     }

src/libflake-tests/.version

@@ -0,0 +1 @@
+../../.version

src/libflake-tests/build-utils-meson

@@ -0,0 +1 @@
+../../build-utils-meson

src/libflake-tests/flakeref.cc

@@ -0,0 +1,24 @@
+#include <gtest/gtest.h>
+
+#include "fetch-settings.hh"
+#include "flake/flakeref.hh"
+
+namespace nix {
+
+/* ----------- tests for flake/flakeref.hh --------------------------------------------------*/
+
+    /* ----------------------------------------------------------------------------
+     * to_string
+     * --------------------------------------------------------------------------*/
+
+    TEST(to_string, doesntReencodeUrl) {
+        fetchers::Settings fetchSettings;
+        auto s = "http://localhost:8181/test/+3d.tar.gz";
+        auto flakeref = parseFlakeRef(fetchSettings, s);
+        auto parsed = flakeref.to_string();
+        auto expected = "http://localhost:8181/test/%2B3d.tar.gz";
+
+        ASSERT_EQ(parsed, expected);
+    }
+
+}

src/libflake-tests/local.mk

@@ -0,0 +1,43 @@
+check: libflake-tests_RUN
+
+programs += libflake-tests
+
+libflake-tests_NAME := libnixflake-tests
+
+libflake-tests_ENV := _NIX_TEST_UNIT_DATA=$(d)/data GTEST_OUTPUT=xml:$$testresults/libflake-tests.xml
+
+libflake-tests_DIR := $(d)
+
+ifeq ($(INSTALL_UNIT_TESTS), yes)
+  libflake-tests_INSTALL_DIR := $(checkbindir)
+else
+  libflake-tests_INSTALL_DIR :=
+endif
+
+libflake-tests_SOURCES := \
+    $(wildcard $(d)/*.cc) \
+    $(wildcard $(d)/value/*.cc) \
+    $(wildcard $(d)/flake/*.cc)
+
+libflake-tests_EXTRA_INCLUDES = \
+    -I src/libflake-test-support \
+    -I src/libstore-test-support \
+    -I src/libutil-test-support \
+    $(INCLUDE_libflake) \
+    $(INCLUDE_libexpr) \
+    $(INCLUDE_libfetchers) \
+    $(INCLUDE_libstore) \
+    $(INCLUDE_libutil) \
+
+libflake-tests_CXXFLAGS += $(libflake-tests_EXTRA_INCLUDES)
+
+libflake-tests_LIBS = \
+    libexpr-test-support libstore-test-support libutil-test-support \
+    libflake libexpr libfetchers libstore libutil
+
+libflake-tests_LDFLAGS := -lrapidcheck $(GTEST_LIBS) -lgmock
+
+ifdef HOST_WINDOWS
+  # Increase the default reserved stack size to 65 MB so Nix doesn't run out of space
+  libflake-tests_LDFLAGS += -Wl,--stack,$(shell echo $$((65 * 1024 * 1024)))
+endif

src/libflake-tests/meson.build

@@ -0,0 +1,74 @@
+project('nix-flake-tests', 'cpp',
+  version : files('.version'),
+  default_options : [
+    'cpp_std=c++2a',
+    # TODO(Qyriad): increase the warning level
+    'warning_level=1',
+    'debug=true',
+    'optimization=2',
+    'errorlogs=true', # Please print logs for tests that fail
+  ],
+  meson_version : '>= 1.1',
+  license : 'LGPL-2.1-or-later',
+)
+
+cxx = meson.get_compiler('cpp')
+
+subdir('build-utils-meson/deps-lists')
+
+deps_private_maybe_subproject = [
+  dependency('nix-expr-test-support'),
+  dependency('nix-flake'),
+]
+deps_public_maybe_subproject = [
+]
+subdir('build-utils-meson/subprojects')
+
+subdir('build-utils-meson/threads')
+
+subdir('build-utils-meson/export-all-symbols')
+
+rapidcheck = dependency('rapidcheck')
+deps_private += rapidcheck
+
+gtest = dependency('gtest', main : true)
+deps_private += gtest
+
+add_project_arguments(
+  # TODO(Qyriad): Yes this is how the autoconf+Make system did it.
+  # It would be nice for our headers to be idempotent instead.
+  '-include', 'config-util.hh',
+  '-include', 'config-store.hh',
+  '-include', 'config-expr.hh',
+  language : 'cpp',
+)
+
+subdir('build-utils-meson/diagnostics')
+
+sources = files(
+  'flakeref.cc',
+  'url-name.cc',
+)
+
+include_dirs = [include_directories('.')]
+
+
+this_exe = executable(
+  meson.project_name(),
+  sources,
+  dependencies : deps_private_subproject + deps_private + deps_other,
+  include_directories : include_dirs,
+  # TODO: -lrapidcheck, see ../libutil-support/build.meson
+  link_args: linker_export_flags + ['-lrapidcheck'],
+  # get main from gtest
+  install : true,
+)
+
+test(
+  meson.project_name(),
+  this_exe,
+  env : {
+    '_NIX_TEST_UNIT_DATA': meson.current_source_dir() / 'data',
+  },
+  protocol : 'gtest',
+)

src/libflake-tests/package.nix

@@ -0,0 +1,81 @@
+{ lib
+, buildPackages
+, stdenv
+, mkMesonExecutable
+
+, nix-flake
+, nix-expr-test-support
+
+, rapidcheck
+, gtest
+, runCommand
+
+# Configuration Options
+
+, version
+, resolvePath
+}:
+
+let
+  inherit (lib) fileset;
+in
+
+mkMesonExecutable (finalAttrs: {
+  pname = "nix-flake-tests";
+  inherit version;
+
+  workDir = ./.;
+  fileset = fileset.unions [
+    ../../build-utils-meson
+    ./build-utils-meson
+    ../../.version
+    ./.version
+    ./meson.build
+    # ./meson.options
+    (fileset.fileFilter (file: file.hasExt "cc") ./.)
+    (fileset.fileFilter (file: file.hasExt "hh") ./.)
+  ];
+
+  buildInputs = [
+    nix-flake
+    nix-expr-test-support
+    rapidcheck
+    gtest
+  ];
+
+  preConfigure =
+    # "Inline" .version so it's not a symlink, and includes the suffix.
+    # Do the meson utils, without modification.
+    ''
+      chmod u+w ./.version
+      echo ${version} > ../../.version
+    '';
+
+  mesonFlags = [
+  ];
+
+  env = lib.optionalAttrs (stdenv.isLinux && !(stdenv.hostPlatform.isStatic && stdenv.system == "aarch64-linux")) {
+    LDFLAGS = "-fuse-ld=gold";
+  };
+
+  passthru = {
+    tests = {
+      run = runCommand "${finalAttrs.pname}-run" {
+        meta.broken = !stdenv.hostPlatform.emulatorAvailable buildPackages;
+      } (lib.optionalString stdenv.hostPlatform.isWindows ''
+        export HOME="$PWD/home-dir"
+        mkdir -p "$HOME"
+      '' + ''
+        export _NIX_TEST_UNIT_DATA=${resolvePath ./data}
+        ${stdenv.hostPlatform.emulator buildPackages} ${lib.getExe finalAttrs.finalPackage}
+        touch $out
+      '');
+    };
+  };
+
+  meta = {
+    platforms = lib.platforms.unix ++ lib.platforms.windows;
+    mainProgram = finalAttrs.pname + stdenv.hostPlatform.extensions.executable;
+  };
+
+})

src/libflake-tests/url-name.cc

@@ -0,0 +1,70 @@
+#include "flake/url-name.hh"
+#include <gtest/gtest.h>
+
+namespace nix {
+
+/* ----------- tests for url-name.hh --------------------------------------------------*/
+
+    TEST(getNameFromURL, getNameFromURL) {
+        ASSERT_EQ(getNameFromURL(parseURL("path:/home/user/project")), "project");
+        ASSERT_EQ(getNameFromURL(parseURL("path:~/repos/nixpkgs#packages.x86_64-linux.hello")), "hello");
+        ASSERT_EQ(getNameFromURL(parseURL("path:~/repos/nixpkgs#legacyPackages.x86_64-linux.hello")), "hello");
+        ASSERT_EQ(getNameFromURL(parseURL("path:~/repos/nixpkgs#packages.x86_64-linux.Hello")), "Hello");
+        ASSERT_EQ(getNameFromURL(parseURL("path:.#nonStandardAttr.mylaptop")), "mylaptop");
+        ASSERT_EQ(getNameFromURL(parseURL("path:./repos/myflake#nonStandardAttr.mylaptop")), "mylaptop");
+        ASSERT_EQ(getNameFromURL(parseURL("path:./nixpkgs#packages.x86_64-linux.complex^bin,man")), "complex");
+        ASSERT_EQ(getNameFromURL(parseURL("path:./myproj#packages.x86_64-linux.default^*")), "myproj");
+        ASSERT_EQ(getNameFromURL(parseURL("path:./myproj#defaultPackage.x86_64-linux")), "myproj");
+
+        ASSERT_EQ(getNameFromURL(parseURL("github:NixOS/nixpkgs#packages.x86_64-linux.hello")), "hello");
+        ASSERT_EQ(getNameFromURL(parseURL("github:NixOS/nixpkgs#hello")), "hello");
+        ASSERT_EQ(getNameFromURL(parseURL("github:NixOS/nix#packages.x86_64-linux.default")), "nix");
+        ASSERT_EQ(getNameFromURL(parseURL("github:NixOS/nix#")), "nix");
+        ASSERT_EQ(getNameFromURL(parseURL("github:NixOS/nix")), "nix");
+        ASSERT_EQ(getNameFromURL(parseURL("github:cachix/devenv/main#packages.x86_64-linux.default")), "devenv");
+        ASSERT_EQ(getNameFromURL(parseURL("github:edolstra/nix-warez?rev=1234&dir=blender&ref=master")), "blender");
+
+        ASSERT_EQ(getNameFromURL(parseURL("gitlab:NixOS/nixpkgs#packages.x86_64-linux.hello")), "hello");
+        ASSERT_EQ(getNameFromURL(parseURL("gitlab:NixOS/nixpkgs#hello")), "hello");
+        ASSERT_EQ(getNameFromURL(parseURL("gitlab:NixOS/nix#packages.x86_64-linux.default")), "nix");
+        ASSERT_EQ(getNameFromURL(parseURL("gitlab:NixOS/nix#")), "nix");
+        ASSERT_EQ(getNameFromURL(parseURL("gitlab:NixOS/nix")), "nix");
+        ASSERT_EQ(getNameFromURL(parseURL("gitlab:cachix/devenv/main#packages.x86_64-linux.default")), "devenv");
+
+        ASSERT_EQ(getNameFromURL(parseURL("sourcehut:NixOS/nixpkgs#packages.x86_64-linux.hello")), "hello");
+        ASSERT_EQ(getNameFromURL(parseURL("sourcehut:NixOS/nixpkgs#hello")), "hello");
+        ASSERT_EQ(getNameFromURL(parseURL("sourcehut:NixOS/nix#packages.x86_64-linux.default")), "nix");
+        ASSERT_EQ(getNameFromURL(parseURL("sourcehut:NixOS/nix#")), "nix");
+        ASSERT_EQ(getNameFromURL(parseURL("sourcehut:NixOS/nix")), "nix");
+        ASSERT_EQ(getNameFromURL(parseURL("sourcehut:cachix/devenv/main#packages.x86_64-linux.default")), "devenv");
+
+        ASSERT_EQ(getNameFromURL(parseURL("git://github.com/edolstra/dwarffs")), "dwarffs");
+        ASSERT_EQ(getNameFromURL(parseURL("git://github.com/edolstra/nix-warez?dir=blender")), "blender");
+        ASSERT_EQ(getNameFromURL(parseURL("git+file:///home/user/project")), "project");
+        ASSERT_EQ(getNameFromURL(parseURL("git+file:///home/user/project?ref=fa1e2d23a22")), "project");
+        ASSERT_EQ(getNameFromURL(parseURL("git+ssh://git@github.com/someuser/my-repo#")), "my-repo");
+        ASSERT_EQ(getNameFromURL(parseURL("git+git://github.com/someuser/my-repo?rev=v1.2.3")), "my-repo");
+        ASSERT_EQ(getNameFromURL(parseURL("git+ssh:///home/user/project?dir=subproject&rev=v2.4")), "subproject");
+        ASSERT_EQ(getNameFromURL(parseURL("git+http://not-even-real#packages.x86_64-linux.hello")), "hello");
+        ASSERT_EQ(getNameFromURL(parseURL("git+https://not-even-real#packages.aarch64-darwin.hello")), "hello");
+
+        ASSERT_EQ(getNameFromURL(parseURL("tarball+http://github.com/NixOS/nix/archive/refs/tags/2.18.1#packages.x86_64-linux.jq")), "jq");
+        ASSERT_EQ(getNameFromURL(parseURL("tarball+https://github.com/NixOS/nix/archive/refs/tags/2.18.1#packages.x86_64-linux.hg")), "hg");
+        ASSERT_EQ(getNameFromURL(parseURL("tarball+file:///home/user/Downloads/nixpkgs-2.18.1#packages.aarch64-darwin.ripgrep")), "ripgrep");
+
+        ASSERT_EQ(getNameFromURL(parseURL("https://github.com/NixOS/nix/archive/refs/tags/2.18.1.tar.gz#packages.x86_64-linux.pv")), "pv");
+        ASSERT_EQ(getNameFromURL(parseURL("http://github.com/NixOS/nix/archive/refs/tags/2.18.1.tar.gz#packages.x86_64-linux.pv")), "pv");
+
+        ASSERT_EQ(getNameFromURL(parseURL("file:///home/user/project?ref=fa1e2d23a22")), "project");
+        ASSERT_EQ(getNameFromURL(parseURL("file+file:///home/user/project?ref=fa1e2d23a22")), "project");
+        ASSERT_EQ(getNameFromURL(parseURL("file+http://not-even-real#packages.x86_64-linux.hello")), "hello");
+        ASSERT_EQ(getNameFromURL(parseURL("file+http://gitfantasy.com/org/user/notaflake")), "notaflake");
+        ASSERT_EQ(getNameFromURL(parseURL("file+https://not-even-real#packages.aarch64-darwin.hello")), "hello");
+
+        ASSERT_EQ(getNameFromURL(parseURL("https://www.github.com/")), std::nullopt);
+        ASSERT_EQ(getNameFromURL(parseURL("path:.")), std::nullopt);
+        ASSERT_EQ(getNameFromURL(parseURL("file:.#")), std::nullopt);
+        ASSERT_EQ(getNameFromURL(parseURL("path:.#packages.x86_64-linux.default")), std::nullopt);
+        ASSERT_EQ(getNameFromURL(parseURL("path:.#packages.x86_64-linux.default^*")), std::nullopt);
+    }
+}

src/libstore-test-support/.version

@@ -0,0 +1 @@
+../../.version

src/libstore-test-support/build-utils-meson

@@ -0,0 +1 @@
+../../build-utils-meson

src/libstore-test-support/local.mk

@@ -0,0 +1,21 @@
+libraries += libstore-test-support
+
+libstore-test-support_NAME = libnixstore-test-support
+
+libstore-test-support_DIR := $(d)
+
+ifeq ($(INSTALL_UNIT_TESTS), yes)
+  libstore-test-support_INSTALL_DIR := $(checklibdir)
+else
+  libstore-test-support_INSTALL_DIR :=
+endif
+
+libstore-test-support_SOURCES := $(wildcard $(d)/tests/*.cc)
+
+libstore-test-support_CXXFLAGS += $(libstore-tests_EXTRA_INCLUDES)
+
+libstore-test-support_LIBS = \
+    libutil-test-support \
+    libstore libutil
+
+libstore-test-support_LDFLAGS := $(THREAD_LDFLAGS) -lrapidcheck

src/libstore-test-support/meson.build

@@ -0,0 +1,78 @@
+project('nix-store-test-support', 'cpp',
+  version : files('.version'),
+  default_options : [
+    'cpp_std=c++2a',
+    # TODO(Qyriad): increase the warning level
+    'warning_level=1',
+    'debug=true',
+    'optimization=2',
+    'errorlogs=true', # Please print logs for tests that fail
+  ],
+  meson_version : '>= 1.1',
+  license : 'LGPL-2.1-or-later',
+)
+
+cxx = meson.get_compiler('cpp')
+
+subdir('build-utils-meson/deps-lists')
+
+deps_private_maybe_subproject = [
+]
+deps_public_maybe_subproject = [
+  dependency('nix-util'),
+  dependency('nix-util-test-support'),
+  dependency('nix-store'),
+]
+subdir('build-utils-meson/subprojects')
+
+subdir('build-utils-meson/threads')
+
+rapidcheck = dependency('rapidcheck')
+deps_public += rapidcheck
+
+add_project_arguments(
+  # TODO(Qyriad): Yes this is how the autoconf+Make system did it.
+  # It would be nice for our headers to be idempotent instead.
+  '-include', 'config-util.hh',
+  '-include', 'config-store.hh',
+  language : 'cpp',
+)
+
+subdir('build-utils-meson/diagnostics')
+
+sources = files(
+  'tests/derived-path.cc',
+  'tests/outputs-spec.cc',
+  'tests/path.cc',
+)
+
+include_dirs = [include_directories('.')]
+
+headers = files(
+  'tests/derived-path.hh',
+  'tests/libstore.hh',
+  'tests/nix_api_store.hh',
+  'tests/outputs-spec.hh',
+  'tests/path.hh',
+  'tests/protocol.hh',
+)
+
+subdir('build-utils-meson/export-all-symbols')
+
+this_library = library(
+  'nix-store-test-support',
+  sources,
+  dependencies : deps_public + deps_private + deps_other,
+  include_directories : include_dirs,
+  # TODO: Remove `-lrapidcheck` when https://github.com/emil-e/rapidcheck/pull/326
+  #       is available. See also ../libutil/build.meson
+  link_args: linker_export_flags + ['-lrapidcheck'],
+  prelink : true, # For C++ static initializers
+  install : true,
+)
+
+install_headers(headers, subdir : 'nix', preserve_path : true)
+
+libraries_private = []
+
+subdir('build-utils-meson/export')

src/libstore-test-support/package.nix

@@ -0,0 +1,60 @@
+{ lib
+, stdenv
+, mkMesonLibrary
+
+, nix-util-test-support
+, nix-store
+
+, rapidcheck
+
+# Configuration Options
+
+, version
+}:
+
+let
+  inherit (lib) fileset;
+in
+
+mkMesonLibrary (finalAttrs: {
+  pname = "nix-store-test-support";
+  inherit version;
+
+  workDir = ./.;
+  fileset = fileset.unions [
+    ../../build-utils-meson
+    ./build-utils-meson
+    ../../.version
+    ./.version
+    ./meson.build
+    # ./meson.options
+    (fileset.fileFilter (file: file.hasExt "cc") ./.)
+    (fileset.fileFilter (file: file.hasExt "hh") ./.)
+  ];
+
+  propagatedBuildInputs = [
+    nix-util-test-support
+    nix-store
+    rapidcheck
+  ];
+
+  preConfigure =
+    # "Inline" .version so it's not a symlink, and includes the suffix.
+    # Do the meson utils, without modification.
+    ''
+      chmod u+w ./.version
+      echo ${version} > ../../.version
+    '';
+
+  mesonFlags = [
+  ];
+
+  env = lib.optionalAttrs (stdenv.isLinux && !(stdenv.hostPlatform.isStatic && stdenv.system == "aarch64-linux")) {
+    LDFLAGS = "-fuse-ld=gold";
+  };
+
+  meta = {
+    platforms = lib.platforms.unix ++ lib.platforms.windows;
+  };
+
+})

src/libstore-test-support/tests/derived-path.cc

@@ -0,0 +1,57 @@
+#include <regex>
+
+#include <rapidcheck.h>
+
+#include "tests/derived-path.hh"
+
+namespace rc {
+using namespace nix;
+
+Gen<DerivedPath::Opaque> Arbitrary<DerivedPath::Opaque>::arbitrary()
+{
+    return gen::just(DerivedPath::Opaque {
+        .path = *gen::arbitrary<StorePath>(),
+    });
+}
+
+Gen<SingleDerivedPath::Built> Arbitrary<SingleDerivedPath::Built>::arbitrary()
+{
+    return gen::just(SingleDerivedPath::Built {
+        .drvPath = make_ref<SingleDerivedPath>(*gen::arbitrary<SingleDerivedPath>()),
+        .output = (*gen::arbitrary<StorePathName>()).name,
+    });
+}
+
+Gen<DerivedPath::Built> Arbitrary<DerivedPath::Built>::arbitrary()
+{
+    return gen::just(DerivedPath::Built {
+        .drvPath = make_ref<SingleDerivedPath>(*gen::arbitrary<SingleDerivedPath>()),
+        .outputs = *gen::arbitrary<OutputsSpec>(),
+    });
+}
+
+Gen<SingleDerivedPath> Arbitrary<SingleDerivedPath>::arbitrary()
+{
+    switch (*gen::inRange<uint8_t>(0, std::variant_size_v<SingleDerivedPath::Raw>)) {
+    case 0:
+        return gen::just<SingleDerivedPath>(*gen::arbitrary<SingleDerivedPath::Opaque>());
+    case 1:
+        return gen::just<SingleDerivedPath>(*gen::arbitrary<SingleDerivedPath::Built>());
+    default:
+        assert(false);
+    }
+}
+
+Gen<DerivedPath> Arbitrary<DerivedPath>::arbitrary()
+{
+    switch (*gen::inRange<uint8_t>(0, std::variant_size_v<DerivedPath::Raw>)) {
+    case 0:
+        return gen::just<DerivedPath>(*gen::arbitrary<DerivedPath::Opaque>());
+    case 1:
+        return gen::just<DerivedPath>(*gen::arbitrary<DerivedPath::Built>());
+    default:
+        assert(false);
+    }
+}
+
+}

src/libstore-test-support/tests/derived-path.hh

@@ -0,0 +1,39 @@
+#pragma once
+///@file
+
+#include <rapidcheck/gen/Arbitrary.h>
+
+#include <derived-path.hh>
+
+#include "tests/path.hh"
+#include "tests/outputs-spec.hh"
+
+namespace rc {
+using namespace nix;
+
+template<>
+struct Arbitrary<SingleDerivedPath::Opaque> {
+    static Gen<SingleDerivedPath::Opaque> arbitrary();
+};
+
+template<>
+struct Arbitrary<SingleDerivedPath::Built> {
+    static Gen<SingleDerivedPath::Built> arbitrary();
+};
+
+template<>
+struct Arbitrary<SingleDerivedPath> {
+    static Gen<SingleDerivedPath> arbitrary();
+};
+
+template<>
+struct Arbitrary<DerivedPath::Built> {
+    static Gen<DerivedPath::Built> arbitrary();
+};
+
+template<>
+struct Arbitrary<DerivedPath> {
+    static Gen<DerivedPath> arbitrary();
+};
+
+}

src/libstore-test-support/tests/libstore.hh

@@ -0,0 +1,34 @@
+#pragma once
+///@file
+
+#include <gtest/gtest.h>
+#include <gmock/gmock.h>
+
+#include "store-api.hh"
+
+namespace nix {
+
+class LibStoreTest : public virtual ::testing::Test
+{
+public:
+    static void SetUpTestSuite()
+    {
+        initLibStore(false);
+    }
+
+protected:
+    LibStoreTest()
+        : store(openStore({
+            .variant =
+                StoreReference::Specified{
+                    .scheme = "dummy",
+                },
+            .params = {},
+        }))
+    {
+    }
+
+    ref<Store> store;
+};
+
+} /* namespace nix */

src/libstore-test-support/tests/nix_api_store.hh

@@ -0,0 +1,73 @@
+#pragma once
+///@file
+#include "tests/nix_api_util.hh"
+
+#include "file-system.hh"
+#include <filesystem>
+
+#include "nix_api_store.h"
+#include "nix_api_store_internal.h"
+
+#include <filesystem>
+#include <gtest/gtest.h>
+
+namespace fs { using namespace std::filesystem; }
+
+namespace nixC {
+class nix_api_store_test : public nix_api_util_context
+{
+public:
+    nix_api_store_test()
+    {
+        nix_libstore_init(ctx);
+        init_local_store();
+    };
+
+    ~nix_api_store_test() override
+    {
+        nix_store_free(store);
+
+        for (auto & path : fs::recursive_directory_iterator(nixDir)) {
+            fs::permissions(path, fs::perms::owner_all);
+        }
+        fs::remove_all(nixDir);
+    }
+
+    Store * store;
+    std::string nixDir;
+    std::string nixStoreDir;
+
+protected:
+    void init_local_store()
+    {
+#ifdef _WIN32
+        // no `mkdtemp` with MinGW
+        auto tmpl = nix::defaultTempDir() + "/tests_nix-store.";
+        for (size_t i = 0; true; ++i) {
+            nixDir = tmpl + std::string { i };
+            if (fs::create_directory(nixDir)) break;
+        }
+#else
+        // resolve any symlinks in i.e. on macOS /tmp -> /private/tmp
+        // because this is not allowed for a nix store.
+        auto tmpl = nix::absPath(std::filesystem::path(nix::defaultTempDir()) / "tests_nix-store.XXXXXX", true);
+        nixDir = mkdtemp((char *) tmpl.c_str());
+#endif
+
+        nixStoreDir = nixDir + "/my_nix_store";
+
+        // Options documented in `nix help-stores`
+        const char * p1[] = {"store", nixStoreDir.c_str()};
+        const char * p2[] = {"state", (new std::string(nixDir + "/my_state"))->c_str()};
+        const char * p3[] = {"log", (new std::string(nixDir + "/my_log"))->c_str()};
+
+        const char ** params[] = {p1, p2, p3, nullptr};
+
+        store = nix_store_open(ctx, "local", params);
+        if (!store) {
+            std::string errMsg = nix_err_msg(nullptr, ctx, nullptr);
+            ASSERT_NE(store, nullptr) << "Could not open store: " << errMsg;
+        };
+    }
+};
+}

src/libstore-test-support/tests/outputs-spec.cc

@@ -0,0 +1,24 @@
+#include "tests/outputs-spec.hh"
+
+#include <rapidcheck.h>
+
+namespace rc {
+using namespace nix;
+
+Gen<OutputsSpec> Arbitrary<OutputsSpec>::arbitrary()
+{
+    switch (*gen::inRange<uint8_t>(0, std::variant_size_v<OutputsSpec::Raw>)) {
+    case 0:
+        return gen::just((OutputsSpec) OutputsSpec::All { });
+    case 1:
+        return gen::just((OutputsSpec) OutputsSpec::Names {
+            *gen::nonEmpty(gen::container<StringSet>(gen::map(
+                gen::arbitrary<StorePathName>(),
+                [](StorePathName n) { return n.name; }))),
+        });
+    default:
+        assert(false);
+    }
+}
+
+}

src/libstore-test-support/tests/outputs-spec.hh

@@ -0,0 +1,18 @@
+#pragma once
+///@file
+
+#include <rapidcheck/gen/Arbitrary.h>
+
+#include <outputs-spec.hh>
+
+#include "tests/path.hh"
+
+namespace rc {
+using namespace nix;
+
+template<>
+struct Arbitrary<OutputsSpec> {
+    static Gen<OutputsSpec> arbitrary();
+};
+
+}

src/libstore-test-support/tests/path.cc

@@ -0,0 +1,80 @@
+#include <rapidcheck/gen/Arbitrary.h>
+#include <regex>
+
+#include <rapidcheck.h>
+
+#include "path-regex.hh"
+#include "store-api.hh"
+
+#include "tests/hash.hh"
+#include "tests/path.hh"
+
+namespace nix {
+
+void showValue(const StorePath & p, std::ostream & os)
+{
+    os << p.to_string();
+}
+
+}
+
+namespace rc {
+using namespace nix;
+
+Gen<char> storePathChar()
+{
+    return rc::gen::apply([](uint8_t i) -> char {
+        switch (i) {
+            case 0 ... 9:
+                return '0' + i;
+            case 10 ... 35:
+                return 'A' + (i - 10);
+            case 36 ... 61:
+                return 'a' + (i - 36);
+            case 62:
+                return '+';
+            case 63:
+                return '-';
+            case 64:
+                return '.';
+            case 65:
+                return '_';
+            case 66:
+                return '?';
+            case 67:
+                return '=';
+            default:
+                assert(false);
+        }
+    },
+    gen::inRange<uint8_t>(0, 10 + 2 * 26 + 6));
+}
+
+Gen<StorePathName> Arbitrary<StorePathName>::arbitrary()
+{
+    return gen::construct<StorePathName>(
+        gen::suchThat(
+            gen::container<std::string>(storePathChar()),
+            [](const std::string & s) {
+                return
+                    !( s == ""
+                    || s == "."
+                    || s == ".."
+                    || s.starts_with(".-")
+                    || s.starts_with("..-")
+                    );
+            }
+        )
+    );
+}
+
+Gen<StorePath> Arbitrary<StorePath>::arbitrary()
+{
+    return
+        gen::construct<StorePath>(
+            gen::arbitrary<Hash>(),
+            gen::apply([](StorePathName n){ return n.name; }, gen::arbitrary<StorePathName>())
+        );
+}
+
+} // namespace rc

src/libstore-test-support/tests/path.hh

@@ -0,0 +1,32 @@
+#pragma once
+///@file
+
+#include <rapidcheck/gen/Arbitrary.h>
+
+#include <path.hh>
+
+namespace nix {
+
+struct StorePathName {
+    std::string name;
+};
+
+// For rapidcheck
+void showValue(const StorePath & p, std::ostream & os);
+
+}
+
+namespace rc {
+using namespace nix;
+
+template<>
+struct Arbitrary<StorePathName> {
+    static Gen<StorePathName> arbitrary();
+};
+
+template<>
+struct Arbitrary<StorePath> {
+    static Gen<StorePath> arbitrary();
+};
+
+}

src/libstore-test-support/tests/protocol.hh

@@ -0,0 +1,75 @@
+#pragma once
+///@file
+
+#include <nlohmann/json.hpp>
+#include <gtest/gtest.h>
+
+#include "tests/libstore.hh"
+#include "tests/characterization.hh"
+
+namespace nix {
+
+template<class Proto, const char * protocolDir>
+class ProtoTest : public CharacterizationTest, public LibStoreTest
+{
+    std::filesystem::path unitTestData = getUnitTestData() / protocolDir;
+
+    std::filesystem::path goldenMaster(std::string_view testStem) const override {
+        return unitTestData / (std::string { testStem + ".bin" });
+    }
+};
+
+template<class Proto, const char * protocolDir>
+class VersionedProtoTest : public ProtoTest<Proto, protocolDir>
+{
+public:
+    /**
+     * Golden test for `T` reading
+     */
+    template<typename T>
+    void readProtoTest(PathView testStem, typename Proto::Version version, T expected)
+    {
+        CharacterizationTest::readTest(testStem, [&](const auto & encoded) {
+            T got = ({
+                StringSource from { encoded };
+                Proto::template Serialise<T>::read(
+                    *LibStoreTest::store,
+                    typename Proto::ReadConn {
+                        .from = from,
+                        .version = version,
+                    });
+            });
+
+            ASSERT_EQ(got, expected);
+        });
+    }
+
+    /**
+     * Golden test for `T` write
+     */
+    template<typename T>
+    void writeProtoTest(PathView testStem, typename Proto::Version version, const T & decoded)
+    {
+        CharacterizationTest::writeTest(testStem, [&]() {
+            StringSink to;
+            Proto::template Serialise<T>::write(
+                *LibStoreTest::store,
+                typename Proto::WriteConn {
+                    .to = to,
+                    .version = version,
+                },
+                decoded);
+            return std::move(to.s);
+        });
+    }
+};
+
+#define VERSIONED_CHARACTERIZATION_TEST(FIXTURE, NAME, STEM, VERSION, VALUE) \
+    TEST_F(FIXTURE, NAME ## _read) { \
+        readProtoTest(STEM, VERSION, VALUE); \
+    } \
+    TEST_F(FIXTURE, NAME ## _write) { \
+        writeProtoTest(STEM, VERSION, VALUE); \
+    }
+
+}

src/libstore-tests/.version

@@ -0,0 +1 @@
+../../.version

src/libstore-tests/build-utils-meson

@@ -0,0 +1 @@
+../../build-utils-meson

src/libstore-tests/common-protocol.cc

@@ -0,0 +1,187 @@
+#include <regex>
+
+#include <nlohmann/json.hpp>
+#include <gtest/gtest.h>
+
+#include "common-protocol.hh"
+#include "common-protocol-impl.hh"
+#include "build-result.hh"
+#include "tests/protocol.hh"
+#include "tests/characterization.hh"
+
+namespace nix {
+
+const char commonProtoDir[] = "common-protocol";
+
+class CommonProtoTest : public ProtoTest<CommonProto, commonProtoDir>
+{
+public:
+    /**
+     * Golden test for `T` reading
+     */
+    template<typename T>
+    void readProtoTest(PathView testStem, const T & expected)
+    {
+        CharacterizationTest::readTest(testStem, [&](const auto & encoded) {
+            T got = ({
+                StringSource from { encoded };
+                CommonProto::Serialise<T>::read(
+                    *store,
+                    CommonProto::ReadConn { .from = from });
+            });
+
+            ASSERT_EQ(got, expected);
+        });
+    }
+
+    /**
+     * Golden test for `T` write
+     */
+    template<typename T>
+    void writeProtoTest(PathView testStem, const T & decoded)
+    {
+        CharacterizationTest::writeTest(testStem, [&]() -> std::string {
+            StringSink to;
+            CommonProto::Serialise<T>::write(
+                *store,
+                CommonProto::WriteConn { .to = to },
+                decoded);
+            return to.s;
+        });
+    }
+};
+
+#define CHARACTERIZATION_TEST(NAME, STEM, VALUE) \
+    TEST_F(CommonProtoTest, NAME ## _read) { \
+        readProtoTest(STEM, VALUE); \
+    } \
+    TEST_F(CommonProtoTest, NAME ## _write) { \
+        writeProtoTest(STEM, VALUE); \
+    }
+
+CHARACTERIZATION_TEST(
+    string,
+    "string",
+    (std::tuple<std::string, std::string, std::string, std::string, std::string> {
+        "",
+        "hi",
+        "white rabbit",
+        "大白兔",
+        "oh no \0\0\0 what was that!",
+    }))
+
+CHARACTERIZATION_TEST(
+    storePath,
+    "store-path",
+    (std::tuple<StorePath, StorePath> {
+        StorePath { "g1w7hy3qg1w7hy3qg1w7hy3qg1w7hy3q-foo" },
+        StorePath { "g1w7hy3qg1w7hy3qg1w7hy3qg1w7hy3q-foo-bar" },
+    }))
+
+CHARACTERIZATION_TEST(
+    contentAddress,
+    "content-address",
+    (std::tuple<ContentAddress, ContentAddress, ContentAddress> {
+        ContentAddress {
+            .method = ContentAddressMethod::Raw::Text,
+            .hash = hashString(HashAlgorithm::SHA256, "Derive(...)"),
+        },
+        ContentAddress {
+            .method = ContentAddressMethod::Raw::Flat,
+            .hash = hashString(HashAlgorithm::SHA1, "blob blob..."),
+        },
+        ContentAddress {
+            .method = ContentAddressMethod::Raw::NixArchive,
+            .hash = hashString(HashAlgorithm::SHA256, "(...)"),
+        },
+    }))
+
+CHARACTERIZATION_TEST(
+    drvOutput,
+    "drv-output",
+    (std::tuple<DrvOutput, DrvOutput> {
+        {
+            .drvHash = Hash::parseSRI("sha256-FePFYIlMuycIXPZbWi7LGEiMmZSX9FMbaQenWBzm1Sc="),
+            .outputName = "baz",
+        },
+        DrvOutput {
+            .drvHash = Hash::parseSRI("sha256-b4afnqKCO9oWXgYHb9DeQ2berSwOjS27rSd9TxXDc/U="),
+            .outputName = "quux",
+        },
+    }))
+
+CHARACTERIZATION_TEST(
+    realisation,
+    "realisation",
+    (std::tuple<Realisation, Realisation> {
+        Realisation {
+            .id = DrvOutput {
+                .drvHash = Hash::parseSRI("sha256-FePFYIlMuycIXPZbWi7LGEiMmZSX9FMbaQenWBzm1Sc="),
+                .outputName = "baz",
+            },
+            .outPath = StorePath { "g1w7hy3qg1w7hy3qg1w7hy3qg1w7hy3q-foo" },
+            .signatures = { "asdf", "qwer" },
+        },
+        Realisation {
+            .id = {
+                .drvHash = Hash::parseSRI("sha256-FePFYIlMuycIXPZbWi7LGEiMmZSX9FMbaQenWBzm1Sc="),
+                .outputName = "baz",
+            },
+            .outPath = StorePath { "g1w7hy3qg1w7hy3qg1w7hy3qg1w7hy3q-foo" },
+            .signatures = { "asdf", "qwer" },
+            .dependentRealisations = {
+                {
+                    DrvOutput {
+                        .drvHash = Hash::parseSRI("sha256-b4afnqKCO9oWXgYHb9DeQ2berSwOjS27rSd9TxXDc/U="),
+                        .outputName = "quux",
+                    },
+                    StorePath { "g1w7hy3qg1w7hy3qg1w7hy3qg1w7hy3q-foo" },
+                },
+            },
+        },
+    }))
+
+CHARACTERIZATION_TEST(
+    vector,
+    "vector",
+    (std::tuple<std::vector<std::string>, std::vector<std::string>, std::vector<std::string>, std::vector<std::vector<std::string>>> {
+        { },
+        { "" },
+        { "", "foo", "bar" },
+        { {}, { "" }, { "", "1", "2" } },
+    }))
+
+CHARACTERIZATION_TEST(
+    set,
+    "set",
+    (std::tuple<std::set<std::string>, std::set<std::string>, std::set<std::string>, std::set<std::set<std::string>>> {
+        { },
+        { "" },
+        { "", "foo", "bar" },
+        { {}, { "" }, { "", "1", "2" } },
+    }))
+
+CHARACTERIZATION_TEST(
+    optionalStorePath,
+    "optional-store-path",
+    (std::tuple<std::optional<StorePath>, std::optional<StorePath>> {
+        std::nullopt,
+        std::optional {
+            StorePath { "g1w7hy3qg1w7hy3qg1w7hy3qg1w7hy3q-foo-bar" },
+        },
+    }))
+
+CHARACTERIZATION_TEST(
+    optionalContentAddress,
+    "optional-content-address",
+    (std::tuple<std::optional<ContentAddress>, std::optional<ContentAddress>> {
+        std::nullopt,
+        std::optional {
+            ContentAddress {
+                .method = ContentAddressMethod::Raw::Flat,
+                .hash = hashString(HashAlgorithm::SHA1, "blob blob..."),
+            },
+        },
+    }))
+
+}

src/libstore-tests/content-address.cc

@@ -0,0 +1,37 @@
+#include <gtest/gtest.h>
+
+#include "content-address.hh"
+
+namespace nix {
+
+/* ----------------------------------------------------------------------------
+ * ContentAddressMethod::parse, ContentAddressMethod::render
+ * --------------------------------------------------------------------------*/
+
+TEST(ContentAddressMethod, testRoundTripPrintParse_1) {
+    for (ContentAddressMethod cam : {
+        ContentAddressMethod::Raw::Text,
+        ContentAddressMethod::Raw::Flat,
+        ContentAddressMethod::Raw::NixArchive,
+        ContentAddressMethod::Raw::Git,
+    }) {
+        EXPECT_EQ(ContentAddressMethod::parse(cam.render()), cam);
+    }
+}
+
+TEST(ContentAddressMethod, testRoundTripPrintParse_2) {
+    for (const std::string_view camS : {
+        "text",
+        "flat",
+        "nar",
+        "git",
+    }) {
+        EXPECT_EQ(ContentAddressMethod::parse(camS).render(), camS);
+    }
+}
+
+TEST(ContentAddressMethod, testParseContentAddressMethodOptException) {
+    EXPECT_THROW(ContentAddressMethod::parse("narwhal"), UsageError);
+}
+
+}

src/libstore-tests/data/derivation/advanced-attributes-defaults.drv

@@ -0,0 +1 @@
+../../../../tests/functional/derivation/advanced-attributes-defaults.drv

src/libstore-tests/data/derivation/advanced-attributes-defaults.json

@@ -0,0 +1,22 @@
+{
+  "args": [
+    "-c",
+    "echo hello > $out"
+  ],
+  "builder": "/bin/bash",
+  "env": {
+    "builder": "/bin/bash",
+    "name": "advanced-attributes-defaults",
+    "out": "/nix/store/1qsc7svv43m4dw2prh6mvyf7cai5czji-advanced-attributes-defaults",
+    "system": "my-system"
+  },
+  "inputDrvs": {},
+  "inputSrcs": [],
+  "name": "advanced-attributes-defaults",
+  "outputs": {
+    "out": {
+      "path": "/nix/store/1qsc7svv43m4dw2prh6mvyf7cai5czji-advanced-attributes-defaults"
+    }
+  },
+  "system": "my-system"
+}

src/libstore-tests/data/derivation/advanced-attributes-structured-attrs-defaults.drv

@@ -0,0 +1 @@
+../../../../tests/functional/derivation/advanced-attributes-structured-attrs-defaults.drv

src/libstore-tests/data/derivation/advanced-attributes-structured-attrs-defaults.json

@@ -0,0 +1,24 @@
+{
+  "args": [
+    "-c",
+    "echo hello > $out"
+  ],
+  "builder": "/bin/bash",
+  "env": {
+    "__json": "{\"builder\":\"/bin/bash\",\"name\":\"advanced-attributes-structured-attrs-defaults\",\"outputs\":[\"out\",\"dev\"],\"system\":\"my-system\"}",
+    "dev": "/nix/store/8bazivnbipbyi569623skw5zm91z6kc2-advanced-attributes-structured-attrs-defaults-dev",
+    "out": "/nix/store/f8f8nvnx32bxvyxyx2ff7akbvwhwd9dw-advanced-attributes-structured-attrs-defaults"
+  },
+  "inputDrvs": {},
+  "inputSrcs": [],
+  "name": "advanced-attributes-structured-attrs-defaults",
+  "outputs": {
+    "dev": {
+      "path": "/nix/store/8bazivnbipbyi569623skw5zm91z6kc2-advanced-attributes-structured-attrs-defaults-dev"
+    },
+    "out": {
+      "path": "/nix/store/f8f8nvnx32bxvyxyx2ff7akbvwhwd9dw-advanced-attributes-structured-attrs-defaults"
+    }
+  },
+  "system": "my-system"
+}

src/libstore-tests/data/derivation/advanced-attributes-structured-attrs.drv

@@ -0,0 +1 @@
+../../../../tests/functional/derivation/advanced-attributes-structured-attrs.drv

src/libstore-tests/data/derivation/advanced-attributes-structured-attrs.json

@@ -0,0 +1,41 @@
+{
+  "args": [
+    "-c",
+    "echo hello > $out"
+  ],
+  "builder": "/bin/bash",
+  "env": {
+    "__json": "{\"__darwinAllowLocalNetworking\":true,\"__impureHostDeps\":[\"/usr/bin/ditto\"],\"__noChroot\":true,\"__sandboxProfile\":\"sandcastle\",\"allowSubstitutes\":false,\"builder\":\"/bin/bash\",\"impureEnvVars\":[\"UNICORN\"],\"name\":\"advanced-attributes-structured-attrs\",\"outputChecks\":{\"bin\":{\"disallowedReferences\":[\"/nix/store/7rhsm8i393hm1wcsmph782awg1hi2f7x-bar\"],\"disallowedRequisites\":[\"/nix/store/7rhsm8i393hm1wcsmph782awg1hi2f7x-bar\"]},\"dev\":{\"maxClosureSize\":5909,\"maxSize\":789},\"out\":{\"allowedReferences\":[\"/nix/store/3c08bzb71z4wiag719ipjxr277653ynp-foo\"],\"allowedRequisites\":[\"/nix/store/3c08bzb71z4wiag719ipjxr277653ynp-foo\"]}},\"outputs\":[\"out\",\"bin\",\"dev\"],\"preferLocalBuild\":true,\"requiredSystemFeatures\":[\"rainbow\",\"uid-range\"],\"system\":\"my-system\"}",
+    "bin": "/nix/store/pbzb48v0ycf80jgligcp4n8z0rblna4n-advanced-attributes-structured-attrs-bin",
+    "dev": "/nix/store/7xapi8jv7flcz1qq8jhw55ar8ag8hldh-advanced-attributes-structured-attrs-dev",
+    "out": "/nix/store/mpq3l1l1qc2yr50q520g08kprprwv79f-advanced-attributes-structured-attrs"
+  },
+  "inputDrvs": {
+    "/nix/store/4xm4wccqsvagz9gjksn24s7rip2fdy7v-foo.drv": {
+      "dynamicOutputs": {},
+      "outputs": [
+        "out"
+      ]
+    },
+    "/nix/store/plsq5jbr5nhgqwcgb2qxw7jchc09dnl8-bar.drv": {
+      "dynamicOutputs": {},
+      "outputs": [
+        "out"
+      ]
+    }
+  },
+  "inputSrcs": [],
+  "name": "advanced-attributes-structured-attrs",
+  "outputs": {
+    "bin": {
+      "path": "/nix/store/pbzb48v0ycf80jgligcp4n8z0rblna4n-advanced-attributes-structured-attrs-bin"
+    },
+    "dev": {
+      "path": "/nix/store/7xapi8jv7flcz1qq8jhw55ar8ag8hldh-advanced-attributes-structured-attrs-dev"
+    },
+    "out": {
+      "path": "/nix/store/mpq3l1l1qc2yr50q520g08kprprwv79f-advanced-attributes-structured-attrs"
+    }
+  },
+  "system": "my-system"
+}

src/libstore-tests/data/derivation/advanced-attributes.drv

@@ -0,0 +1 @@
+../../../../tests/functional/derivation/advanced-attributes.drv

src/libstore-tests/data/derivation/bad-old-version-dyn-deps.drv

@@ -0,0 +1 @@
+Derive([],[("/nix/store/c015dhfh5l0lp6wxyvdn7bmwhbbr6hr9-dep2.drv",(["cat","dog"],[("cat",["kitten"]),("goose",["gosling"])]))],["/nix/store/c015dhfh5l0lp6wxyvdn7bmwhbbr6hr9-dep1"],"wasm-sel4","foo",["bar","baz"],[("BIG_BAD","WOLF")])

src/libstore-tests/data/derivation/bad-version.drv

@@ -0,0 +1 @@
+DrvWithVersion("invalid-version",[],[("/nix/store/c015dhfh5l0lp6wxyvdn7bmwhbbr6hr9-dep2.drv",["cat","dog"])],["/nix/store/c015dhfh5l0lp6wxyvdn7bmwhbbr6hr9-dep1"],"wasm-sel4","foo",["bar","baz"],[("BIG_BAD","WOLF")])

src/libstore-tests/data/derivation/dynDerivationDeps.drv

@@ -0,0 +1 @@
+DrvWithVersion("xp-dyn-drv",[],[("/nix/store/c015dhfh5l0lp6wxyvdn7bmwhbbr6hr9-dep2.drv",(["cat","dog"],[("cat",["kitten"]),("goose",["gosling"])]))],["/nix/store/c015dhfh5l0lp6wxyvdn7bmwhbbr6hr9-dep1"],"wasm-sel4","foo",["bar","baz"],[("BIG_BAD","WOLF")])

src/libstore-tests/data/derivation/dynDerivationDeps.json

@@ -0,0 +1,38 @@
+{
+  "args": [
+    "bar",
+    "baz"
+  ],
+  "builder": "foo",
+  "env": {
+    "BIG_BAD": "WOLF"
+  },
+  "inputDrvs": {
+    "/nix/store/c015dhfh5l0lp6wxyvdn7bmwhbbr6hr9-dep2.drv": {
+      "dynamicOutputs": {
+        "cat": {
+          "dynamicOutputs": {},
+          "outputs": [
+            "kitten"
+          ]
+        },
+        "goose": {
+          "dynamicOutputs": {},
+          "outputs": [
+            "gosling"
+          ]
+        }
+      },
+      "outputs": [
+        "cat",
+        "dog"
+      ]
+    }
+  },
+  "inputSrcs": [
+    "/nix/store/c015dhfh5l0lp6wxyvdn7bmwhbbr6hr9-dep1"
+  ],
+  "name": "dyn-dep-derivation",
+  "outputs": {},
+  "system": "wasm-sel4"
+}

src/libstore-tests/data/derivation/output-caFixedFlat.json

@@ -0,0 +1,6 @@
+{
+  "hash": "894517c9163c896ec31a2adbd33c0681fd5f45b2c0ef08a64c92a03fb97f390f",
+  "hashAlgo": "sha256",
+  "method": "flat",
+  "path": "/nix/store/rhcg9h16sqvlbpsa6dqm57sbr2al6nzg-drv-name-output-name"
+}

src/libstore-tests/data/derivation/output-caFixedNAR.json

@@ -0,0 +1,6 @@
+{
+  "hash": "894517c9163c896ec31a2adbd33c0681fd5f45b2c0ef08a64c92a03fb97f390f",
+  "hashAlgo": "sha256",
+  "method": "nar",
+  "path": "/nix/store/c015dhfh5l0lp6wxyvdn7bmwhbbr6hr9-drv-name-output-name"
+}

src/libstore-tests/data/derivation/output-caFixedText.json

@@ -0,0 +1,6 @@
+{
+  "hash": "894517c9163c896ec31a2adbd33c0681fd5f45b2c0ef08a64c92a03fb97f390f",
+  "hashAlgo": "sha256",
+  "method": "text",
+  "path": "/nix/store/6s1zwabh956jvhv4w9xcdb5jiyanyxg1-drv-name-output-name"
+}

src/libstore-tests/data/derivation/output-caFloating.json

@@ -0,0 +1,4 @@
+{
+  "hashAlgo": "sha256",
+  "method": "nar"
+}

src/libstore-tests/data/derivation/output-deferred.json

@@ -0,0 +1 @@
+{}

src/libstore-tests/data/derivation/output-impure.json

@@ -0,0 +1,5 @@
+{
+  "hashAlgo": "sha256",
+  "impure": true,
+  "method": "nar"
+}

src/libstore-tests/data/derivation/output-inputAddressed.json

@@ -0,0 +1,3 @@
+{
+  "path": "/nix/store/c015dhfh5l0lp6wxyvdn7bmwhbbr6hr9-drv-name-output-name"
+}

src/libstore-tests/data/derivation/simple.drv

@@ -0,0 +1 @@
+Derive([],[("/nix/store/c015dhfh5l0lp6wxyvdn7bmwhbbr6hr9-dep2.drv",["cat","dog"])],["/nix/store/c015dhfh5l0lp6wxyvdn7bmwhbbr6hr9-dep1"],"wasm-sel4","foo",["bar","baz"],[("BIG_BAD","WOLF")])

src/libstore-tests/data/derivation/simple.json

@@ -0,0 +1,25 @@
+{
+  "args": [
+    "bar",
+    "baz"
+  ],
+  "builder": "foo",
+  "env": {
+    "BIG_BAD": "WOLF"
+  },
+  "inputDrvs": {
+    "/nix/store/c015dhfh5l0lp6wxyvdn7bmwhbbr6hr9-dep2.drv": {
+      "dynamicOutputs": {},
+      "outputs": [
+        "cat",
+        "dog"
+      ]
+    }
+  },
+  "inputSrcs": [
+    "/nix/store/c015dhfh5l0lp6wxyvdn7bmwhbbr6hr9-dep1"
+  ],
+  "name": "simple-derivation",
+  "outputs": {},
+  "system": "wasm-sel4"
+}

src/libstore-tests/data/machines/bad_format

@@ -0,0 +1 @@
+nix@scratchy.labs.cs.uu.nl - - eight

src/libstore-tests/data/machines/valid

@@ -0,0 +1,3 @@
+nix@scratchy.labs.cs.uu.nl  i686-linux      /home/nix/.ssh/id_scratchy_auto        8 1 kvm
+nix@itchy.labs.cs.uu.nl     i686-linux      /home/nix/.ssh/id_scratchy_auto        8 2
+nix@poochie.labs.cs.uu.nl   i686-linux      /home/nix/.ssh/id_scratchy_auto        1 2 kvm benchmark 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