with import ./config.nix;

rec {
  dep1 = mkDerivation {
    name = "check-reqs-dep1";
    builder = builtins.toFile "builder.sh" "mkdir $out; touch $out/file1";
  };

  dep2 = mkDerivation {
    name = "check-reqs-dep2";
    builder = builtins.toFile "builder.sh" "mkdir $out; touch $out/file2";
  };

  deps = mkDerivation {
    name = "check-reqs-deps";
    dep1 = dep1;
    dep2 = dep2;
    builder = builtins.toFile "builder.sh" ''
      mkdir $out
      ln -s $dep1/file1 $out/file1
      ln -s $dep2/file2 $out/file2
    '';
  };

  makeTest =
    nr: allowreqs:
    mkDerivation {
      name = "check-reqs-" + toString nr;
      inherit deps;
      builder = builtins.toFile "builder.sh" ''
        mkdir $out
        ln -s $deps $out/depdir1
      '';
      allowedRequisites = allowreqs;
    };

  # When specifying all the requisites, the build succeeds.
  test1 = makeTest 1 [
    dep1
    dep2
    deps
  ];

  # But missing anything it fails.
  test2 = makeTest 2 [
    dep2
    deps
  ];
  test3 = makeTest 3 [
    dep1
    deps
  ];
  test4 = makeTest 4 [ deps ];
  test5 = makeTest 5 [ ];

  test6 = mkDerivation {
    name = "check-reqs";
    inherit deps;
    builder = builtins.toFile "builder.sh" "mkdir $out; ln -s $deps $out/depdir1";
    disallowedRequisites = [ dep1 ];
  };

  test7 = mkDerivation {
    name = "check-reqs";
    inherit deps;
    builder = builtins.toFile "builder.sh" "mkdir $out; ln -s $deps $out/depdir1";
    disallowedRequisites = [ test1 ];
  };
}
