'Test _check_python_file_is_safe fails when custom escapins is used.'

def test_check_custom_escaping(self):

    linter = PythonLinter()
    results = FileResults('')
    python_file = textwrap.dedent("\n                                                msg    =    mmlans.replace('<',    '&lt;')\n                                ")
    linter.check_python_file_is_safe(python_file, results)
    self.assertEqual(len(results.violations), 1)
    self.assertEqual(results.violations[0].rule, Rules.python_custom_escape)
