pkg: add hot write tests

[rleungx]

What problem does this PR solve?

Issue Number: Ref #7848.

What is changed and how does it work?

Check List

Tests

• Unit test

Release note

None.

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• lhy1024

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[codecov]

Codecov Report

Merging #7851 (89727c1) into master (6822137) will decrease coverage by 0.08%.
The diff coverage is n/a.

❗ Current head 89727c1 differs from pull request most recent head c83a3f8. Consider uploading reports for the commit c83a3f8 to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #7851      +/-   ##
==========================================
- Coverage   73.54%   73.47%   -0.08%     
==========================================
  Files         432      432              
  Lines       47915    47915              
==========================================
- Hits        35241    35204      -37     
- Misses       9636     9663      +27     
- Partials     3038     3048      +10     

Flag	Coverage Δ
unittests	73.47% <ø> (-0.08%)	⬇️

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[rleungx]

/merge

[ti-chi-bot]

@rleungx: It seems you want to merge this PR, I will help you trigger all the tests:

/run-all-tests

You only need to trigger /merge once, and if the CI test fails, you just re-trigger the test that failed and the bot will merge the PR for you after the CI passes.

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[ti-chi-bot]

This pull request has been accepted and is ready to merge.

Commit hash: 89727c1

[ti-chi-bot]

@rleungx: Your PR was out of date, I have automatically updated it for you.

If the CI test fails, you just re-trigger the test that failed and the bot will merge the PR for you after the CI passes.

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the ti-community-infra/tichi repository.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-6.5: #8004.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-7.1: #8054.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-7.5: #8143.