'The `SecureTempFile.tmp_file_id` instance attribute is used as the filename
for the secure temporary file. This attribute should not contain
invalid characters such as \'/\' and \'\' (null).'

def test_tmp_file_id_omits_invalid_chars(self):

    self.assertNotIn('/', self.f.tmp_file_id)
    self.assertNotIn('\x00', self.f.tmp_file_id)
