nix/src/libexpr-tests/trivial.cc

#include "nix/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; }; }"
            )
    );

// The following macros ultimately define 48 tests (16 variations on three
// templates). Each template tests an expression that can be written in 2^4
// different ways, by making four choices about whether to write a particular
// attribute path segment as `x.y = ...;` (collapsed) or `x = { y = ...; };`
// (expanded).
//
// The nestedAttrsetMergeXXXX tests check that the expression
// `{ a.b.c = 1; a.b.d = 2; }` has the same value regardless of how it is
// expanded. (That exact expression is exercised in test
// nestedAttrsetMerge0000, because it is fully collapsed. The test
// nestedAttrsetMerge1001 would instead examine
// `{ a = { b.c = 1; }; a.b = { d = 2; }; }`.)
//
// The nestedAttrsetMergeDupXXXX tests check that the expression
// `{ a.b.c = 1; a.b.c = 2; }` throws a duplicate attribute error, again
// regardless of how it is expanded.
//
// The nestedAttrsetMergeLetXXXX tests check that the expression
// `let a.b.c = 1; a.b.d = 2; in a` has the same value regardless of how it is
// expanded.
#define X_EXPAND_IF0(k, v) k "." v
#define X_EXPAND_IF1(k, v) k " = { " v " };"
#define X4(w, x, y, z) \
    TEST_F(TrivialExpressionTest, nestedAttrsetMerge##w##x##y##z) { \
        auto v = eval("{ a.b = { c = 1; d = 2; }; } == { " \
                X_EXPAND_IF##w("a", X_EXPAND_IF##x("b", "c = 1;")) " " \
                X_EXPAND_IF##y("a", X_EXPAND_IF##z("b", "d = 2;")) " }"); \
        ASSERT_THAT(v, IsTrue()); \
    }; \
    TEST_F(TrivialExpressionTest, nestedAttrsetMergeDup##w##x##y##z) { \
        ASSERT_THROW(eval("{ " \
                X_EXPAND_IF##w("a", X_EXPAND_IF##x("b", "c = 1;")) " " \
                X_EXPAND_IF##y("a", X_EXPAND_IF##z("b", "c = 2;")) " }"), Error); \
    }; \
    TEST_F(TrivialExpressionTest, nestedAttrsetMergeLet##w##x##y##z) { \
        auto v = eval("{ b = { c = 1; d = 2; }; } == (let " \
                X_EXPAND_IF##w("a", X_EXPAND_IF##x("b", "c = 1;")) " " \
                X_EXPAND_IF##y("a", X_EXPAND_IF##z("b", "d = 2;")) " in a)"); \
        ASSERT_THAT(v, IsTrue()); \
    };
#define X3(...) X4(__VA_ARGS__, 0) X4(__VA_ARGS__, 1)
#define X2(...) X3(__VA_ARGS__, 0) X3(__VA_ARGS__, 1)
#define X1(...) X2(__VA_ARGS__, 0) X2(__VA_ARGS__, 1)
    X1(0) X1(1)
#undef X_EXPAND_IF0
#undef X_EXPAND_IF1
#undef X1
#undef X2
#undef X3
#undef X4

    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 */