Bug: Use unittest.mock if it is available

The python mock module is deprecated in recent Python versions. If
unittest.mock is available in the system's python, use that instead.

Fixes: #207

Signed-off-by: Major Hayden <[email protected]>

Author: major

tests/asyncio/future/test_async_future.py

@@ -14,7 +14,10 @@
 
 import asyncio
 
-import mock
+try:
+    from unittest import mock
+except:
+    import mock
 import pytest
 
 from google.api_core import exceptions

tests/asyncio/gapic/test_method_async.py

@@ -15,7 +15,10 @@
 import datetime
 
 from grpc.experimental import aio
-import mock
+try:
+    from unittest import mock
+except:
+    import mock
 import pytest
 
 from google.api_core import (exceptions, gapic_v1, grpc_helpers_async,

tests/asyncio/operations_v1/test_operations_async_client.py

@@ -13,7 +13,10 @@
 # limitations under the License.
 
 from grpc.experimental import aio
-import mock
+try:
+    from unittest import mock
+except:
+    import mock
 import pytest
 
 from google.api_core import (grpc_helpers_async, operations_v1,

tests/asyncio/test_grpc_helpers_async.py

@@ -14,7 +14,10 @@
 
 import grpc
 from grpc.experimental import aio
-import mock
+try:
+    from unittest import mock
+except:
+    import mock
 import pytest
 
 from google.api_core import exceptions

tests/asyncio/test_operation_async.py

@@ -13,7 +13,10 @@
 # limitations under the License.
 
 
-import mock
+try:
+    from unittest import mock
+except:
+    import mock
 import pytest
 
 from google.api_core import exceptions

tests/asyncio/test_page_iterator_async.py

@@ -14,7 +14,10 @@
 
 import inspect
 
-import mock
+try:
+    from unittest import mock
+except:
+    import mock
 import pytest
 
 from google.api_core import page_iterator_async

tests/asyncio/test_retry_async.py

@@ -15,7 +15,10 @@
 import datetime
 import re
 
-import mock
+try:
+    from unittest import mock
+except:
+    import mock
 import pytest
 
 from google.api_core import exceptions

tests/unit/future/test__helpers.py

@@ -12,7 +12,10 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import mock
+try:
+    from unittest import mock
+except:
+    import mock
 
 from google.api_core.future import _helpers
 

tests/unit/future/test_polling.py

@@ -16,7 +16,10 @@
 import threading
 import time
 
-import mock
+try:
+    from unittest import mock
+except:
+    import mock
 import pytest
 
 from google.api_core import exceptions, retry

tests/unit/gapic/test_method.py

@@ -14,7 +14,10 @@
 
 import datetime
 
-import mock
+try:
+    from unittest import mock
+except:
+    import mock
 
 from google.api_core import exceptions
 from google.api_core import retry