def METHOD_NAME(self):
    crtv = tls.CertValidator()
    good_certs = [
        'cert.pem'
    ]
    self.cfg['ssl_key'] = helpers.HTTPS_DATA['key']
    for fname in good_certs:
        p = os.path.join(self.test_data_dir, 'valid', fname)
        with open(p, 'rb') as f:
            self.cfg['ssl_cert'] = f.read()
        ok, err = crtv.validate(self.cfg)
        self.assertTrue(ok)
        self.assertIsNone(err)