tests: add mock for bigquery auth (#313)

tests/unit/extractor/test_bigquery_metadata_extractor.py

@@ -137,6 +137,8 @@ class MockBigQueryClient():
         return self.tables_method
 
 
+# Patch fallback auth method to avoid actually calling google API
+@patch('google.auth.default', lambda scopes: ['dummy', 'dummy'])
 class TestBigQueryMetadataExtractor(unittest.TestCase):
     def setUp(self):
         # type: () -> None

tests/unit/extractor/test_bigquery_usage_extractor.py

@@ -189,6 +189,8 @@ class MockLoggingClient():
         return self.b
 
 
+# Patch fallback auth method to avoid actually calling google API
+@patch('google.auth.default', lambda scopes: ['dummy', 'dummy'])
 class TestBigqueryUsageExtractor(unittest.TestCase):
 
     @patch('databuilder.extractor.base_bigquery_extractor.build')

tests/unit/extractor/test_bigquery_watermark_extractor.py

@@ -83,6 +83,8 @@ class MockBigQueryClient():
         return self.jobs_query
 
 
+# Patch fallback auth method to avoid actually calling google API
+@patch('google.auth.default', lambda scopes: ['dummy', 'dummy'])
 class TestBigQueryWatermarkExtractor(unittest.TestCase):
     def setUp(self):
         # type: () -> None