add unit test for proxyutils

[AiRanthem]

Ⅰ. Describe what this PR does

Ⅱ. Does this pull request fix one issue?

Ⅲ. Describe how to verify it

Ⅳ. Special notes for reviews

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 46.92%. Comparing base (6d65f97) to head (704ea99).
⚠️ Report is 1 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master      #85      +/-   ##
==========================================
+ Coverage   46.55%   46.92%   +0.37%     
==========================================
  Files          78       78              
  Lines        4494     4494              
==========================================
+ Hits         2092     2109      +17     
+ Misses       2208     2190      -18     
- Partials      194      195       +1     

Flag	Coverage Δ
unittests	46.92% <ø> (+0.37%)	⬆️

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[furykerry]

/lgtm
/approve

[kruise-bot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: furykerry

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