def assert_no_error(self, lines):
        def handler(error_handler, line_number, category, confidence, message):
            self.fail('Unexpected error: %d %s %d %s' % (line_number, category, confidence, message))

        error_handler = TestErrorHandler(handler)
        checker = xcodeproj.XcodeProjectFileChecker('', error_handler)
        checker.check(lines)
    def assert_error(self, lines, expected_message):
        self.had_error = False

        def handler(error_handler, line_number, category, confidence, message):
            self.assertEqual(expected_message, message)
            self.had_error = True
        error_handler = TestErrorHandler(handler)
        checker = xcodeproj.XcodeProjectFileChecker('', error_handler)
        checker.check(lines)
        self.assertTrue(self.had_error, '%s should have error: %s.' % (lines, expected_message))