':py:obj:`Context.check_privatekey` returns :py:obj:`None` if the
:py:obj:`Context` instance has been configured to use a matched key and
certificate pair.'

def test_check_privatekey_valid(self):

    key = load_privatekey(FILETYPE_PEM, client_key_pem)
    cert = load_certificate(FILETYPE_PEM, client_cert_pem)
    context = Context(TLSv1_METHOD)
    context.use_privatekey(key)
    context.use_certificate(cert)
    self.assertIs(None, context.check_privatekey())
