refactor: switch from mock to unittest.mock (#34844)

As of Python 3.3, the 3rd-party `mock` package has been subsumed into the
standard `unittest.mock` package. Refactoring tests to use the latter will
allow us to drop `mock` as a dependency, which is currently coming in
transitively through requirements/edx/paver.in.

We don't actually drop the `mock` dependency in this PR. That will happen
naturally in:

* https://github.com/openedx/edx-platform/pull/34830

lms/djangoapps/course_goals/tests/test_user_activity.py

@@ -3,7 +3,7 @@ Unit tests for user activity methods.
 """
 
 from datetime import datetime, timedelta
-from unittest.mock import Mock
+from unittest.mock import Mock, patch
 
 import ddt
 from django.contrib.auth import get_user_model
@@ -12,7 +12,6 @@ from django.urls import reverse
 from edx_django_utils.cache import TieredCache
 from edx_toggles.toggles.testutils import override_waffle_flag
 from freezegun import freeze_time
-from mock import patch
 from xmodule.modulestore.tests.django_utils import ModuleStoreTestCase
 from xmodule.modulestore.tests.factories import CourseFactory, BlockFactory
 

lms/djangoapps/course_home_api/course_metadata/tests/test_views.py

@@ -1,14 +1,13 @@
 """
 Tests for the Course Home Course Metadata API in the Course Home API
 """
+import json
+from unittest.mock import patch
 
 import ddt
-import json
-import mock
 from django.db import transaction
 from django.urls import reverse
 from edx_toggles.toggles.testutils import override_waffle_flag
-from unittest.mock import patch
 
 from common.djangoapps.course_modes.models import CourseMode
 from common.djangoapps.student.models import CourseEnrollment
@@ -108,7 +107,7 @@ class CourseHomeMetadataTests(BaseCourseHomeTests):
         CourseEnrollment.enroll(self.user, self.course.id, 'audit')
         with override_waffle_flag(COURSEWARE_MFE_MILESTONES_STREAK_DISCOUNT, active=True):
             UPDATES_METHOD_NAME = 'common.djangoapps.student.models.user.UserCelebration.perform_streak_updates'
-            with mock.patch(UPDATES_METHOD_NAME, return_value=3):
+            with patch(UPDATES_METHOD_NAME, return_value=3):
                 response = self.client.get(self.url, content_type='application/json')
                 celebrations = response.json()['celebrations']
                 assert celebrations['streak_length_to_celebrate'] == 3
@@ -187,7 +186,7 @@ class CourseHomeMetadataTests(BaseCourseHomeTests):
             self.update_masquerade(role=masquerade_role)
 
         consent_url = 'dump/consent/url' if dsc_required else None
-        with mock.patch('openedx.features.enterprise_support.api.get_enterprise_consent_url', return_value=consent_url):
+        with patch('openedx.features.enterprise_support.api.get_enterprise_consent_url', return_value=consent_url):
             response = self.client.get(self.url)
 
         self._assert_course_access_response(response, expect_course_access, error_code)

lms/djangoapps/discussion/django_comment_client/base/tests.py

@@ -6,15 +6,15 @@ import pytest
 import json
 import logging
 from contextlib import contextmanager
+from unittest import mock
+from unittest.mock import ANY, Mock, patch
 
 import ddt
-import mock
 from django.contrib.auth.models import User
 from django.core.management import call_command
 from django.test.client import RequestFactory
 from django.urls import reverse
 from eventtracking.processors.exceptions import EventEmissionExit
-from mock import ANY, Mock, patch
 from opaque_keys.edx.keys import CourseKey
 from openedx_events.learning.signals import FORUM_THREAD_CREATED, FORUM_THREAD_RESPONSE_CREATED, FORUM_RESPONSE_COMMENT_CREATED
 

lms/djangoapps/instructor/tests/test_tools.py

@@ -7,6 +7,7 @@ import datetime
 import json
 import unittest
 from unittest import mock
+from unittest.mock import MagicMock, patch
 
 import pytest
 from django.contrib.auth.models import User  # lint-amnesty, pylint: disable=imported-auth-user
@@ -14,7 +15,6 @@ from django.core.exceptions import MultipleObjectsReturned
 from django.test import TestCase
 from edx_when.api import get_dates_for_course, set_dates_for_course
 from edx_when.field_data import DateLookupFieldData
-from mock.mock import MagicMock, patch
 from opaque_keys.edx.keys import CourseKey
 from pytz import UTC
 from xmodule.fields import Date

lms/djangoapps/mobile_api/tests/test_course_info_serializers.py

@@ -1,11 +1,11 @@
 """
 Tests for serializers for the Mobile Course Info
 """
+from unittest.mock import MagicMock, Mock, patch
+from typing import Dict, List, Tuple, Union
 
 import ddt
 from django.test import TestCase
-from mock import MagicMock, Mock, patch
-from typing import Dict, List, Tuple, Union
 
 from common.djangoapps.student.tests.factories import UserFactory
 from lms.djangoapps.mobile_api.course_info.serializers import (

lms/djangoapps/mobile_api/tests/test_course_info_views.py

@@ -1,6 +1,7 @@
 """
 Tests for course_info
 """
+from unittest.mock import patch
 
 
 import ddt
@@ -11,7 +12,6 @@ from django.test import RequestFactory
 from django.urls import reverse
 from edx_toggles.toggles.testutils import override_waffle_flag
 from milestones.tests.utils import MilestonesTestCaseMixin
-from mock import patch
 from rest_framework import status
 
 from common.djangoapps.student.tests.factories import UserFactory  # pylint: disable=unused-import