 
     in_tmp context.test, fn ->
       File.mkdir_p!("config/sub")
-      File.write! "config/config.exs", "[]"
-      File.write! "config/dev.exs", "[]"
-      File.write! "config/.exs", "[]"
-      File.write! "config/sub/init.exs", "[]"
+      File.write!("config/config.exs", "[]")
+      File.write!("config/dev.exs", "[]")
+      File.write!("config/.exs", "[]")
+      File.write!("config/sub/init.exs", "[]")
 
-      files = Mix.Project.config_files
+      files = Mix.Project.config_files()
 
       assert __ENV__.file in files
       assert "config/config.exs" in files


  defp assert_proj_dir_linked_or_copied(source, target, symlink_path) do
    case :file.read_link(source) do
      {:ok, path} -> 
        case :os.type do
          # relative symlink on Windows are broken, see symlink_or_copy/2
          {:win32, _} -> 
            assert path == [source, '..', symlink_path] |> Path.join |> Path.expand |> String.to_charlist
          _ ->
            assert path == symlink_path
        end
      {:error, _} -> assert File.ls!(source) == File.ls!(target)
    end
  end
end


  test "in_project pushes given configuration", context do
    in_tmp context.test, fn ->
      result =
        Mix.Project.in_project(:foo, ".", [hello: :world], fn _ ->
          assert Mix.Project.config()[:app] == :foo
          assert Mix.Project.config()[:hello] == :world
          :result
        end)

      assert result == :result
    end
