diff -up ./tests/asyncio/future/test_async_future.py.orig ./tests/asyncio/future/test_async_future.py

--- ./tests/asyncio/future/test_async_future.py.orig	2021-08-23 07:02:16.988893673 -0500

+++ ./tests/asyncio/future/test_async_future.py	2021-08-23 07:05:20.264433127 -0500

@@ -14,7 +14,7 @@

 import asyncio

-import mock

+from unittest import mock

 import pytest

 from google.api_core import exceptions

diff -up ./tests/asyncio/gapic/test_method_async.py.orig ./tests/asyncio/gapic/test_method_async.py

--- ./tests/asyncio/gapic/test_method_async.py.orig	2021-08-23 07:02:16.988893673 -0500

+++ ./tests/asyncio/gapic/test_method_async.py	2021-08-23 07:05:20.265433119 -0500

@@ -15,7 +15,7 @@

 import datetime

 from grpc import aio

-import mock

+from unittest import mock

 import pytest

 from google.api_core import exceptions

diff -up ./tests/asyncio/operations_v1/test_operations_async_client.py.orig ./tests/asyncio/operations_v1/test_operations_async_client.py

--- ./tests/asyncio/operations_v1/test_operations_async_client.py.orig	2021-08-23 07:02:16.988893673 -0500

+++ ./tests/asyncio/operations_v1/test_operations_async_client.py	2021-08-23 07:05:20.265433119 -0500

@@ -13,7 +13,7 @@

 # limitations under the License.

 from grpc import aio

-import mock

+from unittest import mock

 import pytest

 from google.api_core import grpc_helpers_async, operations_v1, page_iterator_async

diff -up ./tests/asyncio/test_grpc_helpers_async.py.orig ./tests/asyncio/test_grpc_helpers_async.py

--- ./tests/asyncio/test_grpc_helpers_async.py.orig	2021-08-23 07:02:16.988893673 -0500

+++ ./tests/asyncio/test_grpc_helpers_async.py	2021-08-23 07:05:20.265433119 -0500

@@ -14,7 +14,7 @@

 import grpc

 from grpc import aio

-import mock

+from unittest import mock

 import pytest

 from google.api_core import exceptions

diff -up ./tests/asyncio/test_operation_async.py.orig ./tests/asyncio/test_operation_async.py

--- ./tests/asyncio/test_operation_async.py.orig	2021-08-23 07:02:16.988893673 -0500

+++ ./tests/asyncio/test_operation_async.py	2021-08-23 07:05:20.266433111 -0500

@@ -13,7 +13,7 @@

 # limitations under the License.

-import mock

+from unittest import mock

 import pytest

 from google.api_core import exceptions

diff -up ./tests/asyncio/test_page_iterator_async.py.orig ./tests/asyncio/test_page_iterator_async.py

--- ./tests/asyncio/test_page_iterator_async.py.orig	2021-08-23 07:02:16.988893673 -0500

+++ ./tests/asyncio/test_page_iterator_async.py	2021-08-23 07:05:20.266433111 -0500

@@ -14,7 +14,7 @@

 import inspect

-import mock

+from unittest import mock

 import pytest

 from google.api_core import page_iterator_async

diff -up ./tests/asyncio/test_retry_async.py.orig ./tests/asyncio/test_retry_async.py

--- ./tests/asyncio/test_retry_async.py.orig	2021-08-23 07:02:16.989893665 -0500

+++ ./tests/asyncio/test_retry_async.py	2021-08-23 07:05:20.267433103 -0500

@@ -15,7 +15,7 @@

 import datetime

 import re

-import mock

+from unittest import mock

 import pytest

 from google.api_core import exceptions

diff -up ./tests/unit/future/test__helpers.py.orig ./tests/unit/future/test__helpers.py

--- ./tests/unit/future/test__helpers.py.orig	2021-08-23 07:02:16.989893665 -0500

+++ ./tests/unit/future/test__helpers.py	2021-08-23 07:05:20.267433103 -0500

@@ -12,7 +12,7 @@

 # See the License for the specific language governing permissions and

 # limitations under the License.

-import mock

+from unittest import mock

 from google.api_core.future import _helpers

diff -up ./tests/unit/future/test_polling.py.orig ./tests/unit/future/test_polling.py

--- ./tests/unit/future/test_polling.py.orig	2021-08-23 07:02:16.989893665 -0500

+++ ./tests/unit/future/test_polling.py	2021-08-23 07:05:20.268433095 -0500

@@ -16,7 +16,7 @@ import concurrent.futures

 import threading

 import time

-import mock

+from unittest import mock

 import pytest

 from google.api_core import exceptions, retry

diff -up ./tests/unit/gapic/test_method.py.orig ./tests/unit/gapic/test_method.py

--- ./tests/unit/gapic/test_method.py.orig	2021-08-23 07:02:16.989893665 -0500

+++ ./tests/unit/gapic/test_method.py	2021-08-23 07:05:20.268433095 -0500

@@ -14,7 +14,7 @@

 import datetime

-import mock

+from unittest import mock

 from google.api_core import exceptions

 from google.api_core import retry

diff -up ./tests/unit/test_bidi.py.orig ./tests/unit/test_bidi.py

--- ./tests/unit/test_bidi.py.orig	2021-08-23 07:02:16.989893665 -0500

+++ ./tests/unit/test_bidi.py	2021-08-23 07:05:20.269433087 -0500

@@ -18,7 +18,7 @@ import queue

 import threading

 import grpc

-import mock

+from unittest import mock

 import pytest

 from google.api_core import bidi

diff -up ./tests/unit/test_exceptions.py.orig ./tests/unit/test_exceptions.py

--- ./tests/unit/test_exceptions.py.orig	2021-08-23 07:02:16.990893657 -0500

+++ ./tests/unit/test_exceptions.py	2021-08-23 07:05:20.269433087 -0500

@@ -16,7 +16,7 @@ import http.client

 import json

 import grpc

-import mock

+from unittest import mock

 import requests

 from google.api_core import exceptions

diff -up ./tests/unit/test_grpc_helpers.py.orig ./tests/unit/test_grpc_helpers.py

--- ./tests/unit/test_grpc_helpers.py.orig	2021-08-23 07:02:16.990893657 -0500

+++ ./tests/unit/test_grpc_helpers.py	2021-08-23 07:05:20.270433079 -0500

@@ -13,7 +13,7 @@

 # limitations under the License.

 import grpc

-import mock

+from unittest import mock

 import pytest

 from google.api_core import exceptions

diff -up ./tests/unit/test_operation.py.orig ./tests/unit/test_operation.py

--- ./tests/unit/test_operation.py.orig	2021-08-23 07:02:16.990893657 -0500

+++ ./tests/unit/test_operation.py	2021-08-23 07:05:20.270433079 -0500

@@ -13,7 +13,7 @@

 # limitations under the License.

-import mock

+from unittest import mock

 from google.api_core import exceptions

 from google.api_core import operation

diff -up ./tests/unit/test_page_iterator.py.orig ./tests/unit/test_page_iterator.py

--- ./tests/unit/test_page_iterator.py.orig	2021-08-23 07:02:16.990893657 -0500

+++ ./tests/unit/test_page_iterator.py	2021-08-23 07:05:20.271433071 -0500

@@ -15,7 +15,7 @@

 import math

 import types

-import mock

+from unittest import mock

 import pytest

 from google.api_core import page_iterator

diff -up ./tests/unit/test_path_template.py.orig ./tests/unit/test_path_template.py

--- ./tests/unit/test_path_template.py.orig	2021-08-23 07:02:16.990893657 -0500

+++ ./tests/unit/test_path_template.py	2021-08-23 07:05:20.271433071 -0500

@@ -14,7 +14,7 @@

 from __future__ import unicode_literals

-import mock

+from unittest import mock

 import pytest

 from google.api_core import path_template

diff -up ./tests/unit/test_retry.py.orig ./tests/unit/test_retry.py

--- ./tests/unit/test_retry.py.orig	2021-08-23 07:02:16.990893657 -0500

+++ ./tests/unit/test_retry.py	2021-08-23 07:05:20.272433063 -0500

@@ -16,7 +16,7 @@ import datetime

 import itertools

 import re

-import mock

+from unittest import mock

 import pytest

 import requests.exceptions

diff -up ./tests/unit/test_timeout.py.orig ./tests/unit/test_timeout.py

--- ./tests/unit/test_timeout.py.orig	2021-08-23 07:02:16.990893657 -0500

+++ ./tests/unit/test_timeout.py	2021-08-23 07:05:20.273433055 -0500

@@ -15,7 +15,7 @@

 import datetime

 import itertools

-import mock

+from unittest import mock

 from google.api_core import timeout