def test_if_matches_failure(self):
        return self.assertResponseCode(
            b"POST", b"/configuration/datasets/%s" % (uuid4(),),
            {u"primary": self.NODE_A},
            PRECONDITION_FAILED,
            additional_headers={IF_MATCHES_HEADER:
                                [b"willnotmatch"]})
If an ``X-If-Configuration-Matches`` header is sent with a
dataset/ETHPy150Open ClusterHQ/flocker/flocker/control/test/test_httpapi.py/UpdatePrimaryDatasetTestsMixin.test_if_matches_failure