def METHOD_NAME(self):
    crtv = tls.CertValidator()
    self.cfg['ssl_key'] = helpers.HTTPS_DATA['key']
    for fname in self.invalid_files:
        p = os.path.join(self.test_data_dir, 'invalid', fname)
        with open(p, 'rb') as f:
            self.cfg['ssl_cert'] = f.read()
        ok, err = crtv.validate(self.cfg)
        self.assertFalse(ok)
        self.assertIsNotNone(err)