[Fix] Fix unit test in windows

[HAOCHENYE]

Thanks for your contribution and we appreciate it a lot. The following instructions would make your pull request more healthy and more easily get feedback. If you do not understand some items, don't worry, just make the pull request and seek help from maintainers.

Motivation

Test windows CI. This PR will be merged to #512

Modification

Please briefly describe what modification is made in this PR.

BC-breaking (Optional)

Does the modification introduce changes that break the backward-compatibility of the downstream repos?
If so, please describe how it breaks the compatibility and how the downstream projects should modify their code to keep compatibility with this PR.

Use cases (Optional)

If this PR introduces a new feature, it is better to list some use cases here, and update the documentation.

Checklist

1. Pre-commit or other linting tools are used to fix the potential lint issues.
2. The modification is covered by complete unit tests. If not, please add more unit test to ensure the correctness.
3. If the modification has potential influence on downstream projects, this PR should be tested with downstream projects, like MMDet or MMCls.
4. The documentation has been modified accordingly, like docstring or example tutorials.

[codecov]

Codecov Report

❗ No coverage uploaded for pull request base (main@ba1c368). Click here to learn what that means.
Patch has no changes to coverable lines.

❗ Current head 0896853 differs from pull request most recent head ad23b3b. Consider uploading reports for the commit ad23b3b to get more accurate results

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #515   +/-   ##
=======================================
  Coverage        ?   77.75%           
=======================================
  Files           ?      116           
  Lines           ?     8605           
  Branches        ?     1775           
=======================================
  Hits            ?     6691           
  Misses          ?     1618           
  Partials        ?      296           

Flag	Coverage Δ
unittests	77.75% <0.00%> (?)

Flags with carried forward coverage won't be shown. Click here to find out more.

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.

☔ View full report at Codecov.
📢 Do you have feedback about the report comment? Let us know in this issue.

[zhouzaida]

This file (tests/test_testing/test_assert_called.py) is empty.

[zhouzaida]

Do we have a more elegant way to shut down those file handlers in the future?

[HAOCHENYE]

We'll provide a TestCase to create and delete global variance.