Fix unit test for mypy

Author: gcomneno

tests/unit/test_commands.py

@@ -1,7 +1,8 @@
-import os
 import logging
+import os
 from typing import Callable
 from unittest import mock
+
 import pytest
 
 from pip._internal.cli.base_command import Command
@@ -171,13 +172,13 @@ def test_handle_pip_version_check_warning_includes_reason(
     options.disable_pip_version_check = False
     options.no_index = False
 
-    dummy_session = mock.MagicMock()
-    dummy_session.__enter__.return_value = dummy_session
-    dummy_session.__exit__.return_value = None
-    cmd._build_session = mock.Mock(return_value=dummy_session)
-
-    with caplog.at_level(logging.WARNING):
-        cmd.handle_pip_version_check(options)
+    with mock.patch.object(
+        cmd,
+        "_build_session",
+        side_effect=PermissionError("Access is denied"),
+    ):
+        with caplog.at_level(logging.WARNING):
+            cmd.handle_pip_version_check(options)
 
     assert "There was an error checking the latest version of pip." in caplog.text
     assert "PermissionError" in caplog.text