added test for no quota project

tests/conftest.py

@@ -42,6 +42,20 @@ def google_auth(monkeypatch):
     return google_auth_mock
 
 
+@pytest.fixture
+def google_auth_no_quota_project(monkeypatch):
+    google_auth_mock = MagicMock()
+    default_credentials_mock = MagicMock(
+        client_id="my_client_id", quota_project_id=None
+    )
+    google_auth_mock.default.side_effect = lambda *args, **kwargs: (
+        default_credentials_mock,
+        "my_project",
+    )
+    monkeypatch.setattr("google.auth", google_auth_mock)
+    return google_auth_mock
+
+
 @pytest.fixture
 def oauth2_credentials(monkeypatch):
     CredentialsMock = MagicMock()

tests/test_credentials.py

@@ -108,6 +108,13 @@ def test_block_initialization_gcloud_cli(google_auth, oauth2_credentials):
     assert gcp_credentials.project == "my_project"
 
 
+def test_block_initialization_metadata_server(
+    google_auth_no_quota_project, oauth2_credentials
+):
+    gcp_credentials = GcpCredentials()
+    assert gcp_credentials.project == "my_project"
+
+
 @pytest.mark.parametrize("override_project", [None, "override_project"])
 def test_get_cloud_storage_client(
     override_project, service_account_info, oauth2_credentials, storage_client