'TestClient.test_ctor_wo_project' fails with `google-cloud-core 1.6.0'

[tseaver]

googleapis/python-cloud-core#51 changed the semantics of default project detection.

$ nox -re unit-3.9
...

=================================== FAILURES ===================================
_______________________ TestClient.test_ctor_wo_project ________________________

self = <tests.unit.test_client.TestClient testMethod=test_ctor_wo_project>

    def test_ctor_wo_project(self):
        from google.cloud.storage._http import Connection
    
        PROJECT = "PROJECT"
        credentials = _make_credentials()
    
        ddp_patch = mock.patch(
            "google.cloud.client._determine_default_project", return_value=PROJECT
        )
    
        with ddp_patch:
            client = self._make_one(credentials=credentials)
    
>       self.assertEqual(client.project, PROJECT)
E       AssertionError: 'precise-truck-742' != 'PROJECT'
E       - precise-truck-742
E       + PROJECT

tests/unit/test_client.py:186: AssertionError
...
$ .nox/unit-3-9/bin/pip show google-cloud-core | grep Version
Version: 1.6.0
$ .nox/unit-3-9/bin/pip install --upgrade "google-cloud-core==1.5.0"
...
Installing collected packages: google-cloud-core
  Attempting uninstall: google-cloud-core
    Found existing installation: google-cloud-core 1.6.0
    Uninstalling google-cloud-core-1.6.0:
      Successfully uninstalled google-cloud-core-1.6.0
Successfully installed google-cloud-core-1.5.0
$ nox -re unit-3.9
nox > Running session unit-3.9
nox > Re-using existing virtual environment at .nox/unit-3-9.
nox > python -m pip install mock pytest pytest-cov
nox > python -m pip install -e .
nox > py.test --quiet --cov=google.cloud.storage --cov=google.cloud --cov=tests.unit --cov-append --cov-config=.coveragerc --cov-report= --cov-fail-under=0 tests/unit
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Coverage.py warning: Module google.cloud was previously imported, but not measured (module-not-measured)



920 passed, 1 skipped in 13.93s
nox > Session unit-3.9 was successful.