   defp test_content(Test[expected: { :error, exception, message }] = test, module, do_import) do
     line = test.line
     file = module.__info__(:compile)[:source]
+    location = [line: line, file: Path.relative_to(file, System.cwd!)]
+    stack    = Macro.escape [{ module, :__MODULE__, 0, location }]
 
     expr_ast = string_to_ast(line, file, test.expr)
 

    :"test doc at #{inspect m}.#{f}/#{a} (#{n})"
  end

  defp test_content(Test[expected: { :ok, expected }] = test, module, do_import) do
    line = test.line
    file = module.__info__(:compile)[:source]

    expr_ast     = string_to_ast(line, file, test.expr)
    expected_ast = string_to_ast(line, file, expected)

        case unquote(expr_ast) do
          ^v -> :ok
          instead ->
            raise ExUnit.ExpectationError,
              [ prelude: "Expected doctest",
                expected: unquote(test.expr),
                actual: inspect(v),
                reason: "evaluate to",
                instead: instead ],
              unquote(stack)
        end
      rescue
        e in [ExUnit.ExpectationError] ->
          raise e, [], unquote(stack)
        e ->
          raise ExUnit.ExpectationError,
            [ prelude: "Expected doctest",
              expected: unquote(test.expr),
              actual: "without an exception",
              reason: "complete",
              instead: e ],
            unquote(stack)
      end
    end
    if do_import do
