{ pkgs, haskellPackages }:

let
  # This can be regenerated by running `cabal2nix ./src` in the current directory.
  pkgDef =
    {
      mkDerivation,
      base,
      lib,
    }:
    mkDerivation {
      pname = "haskell-setBuildTarget";
      version = "0.1.0.0";
      src = ./src;
      isLibrary = false;
      isExecutable = true;
      executableHaskellDepends = [ base ];
      license = "unknown";
    };

  drv = haskellPackages.callPackage pkgDef { };

  test =
    target: excluded:
    let
      only = pkgs.haskell.lib.compose.setBuildTarget target drv;
    in
    ''
      if [[ ! -f "${only}/bin/${target}" ]]; then
        echo "${target} was not built"
        exit 1
      fi

      if [[ -f "${only}/bin/${excluded}" ]]; then
        echo "${excluded} was built, when it should not have been"
        exit 1
      fi
    '';

in
pkgs.runCommand "test haskell.lib.compose.setBuildTarget"
  {
    meta = {
      inherit (drv.meta) platforms;
    };
  }
  ''
    ${test "foo" "bar"}
    ${test "bar" "foo"}
    touch "$out"
  ''