test: fix TestWatchKeyspace

[AmoebaProtozoa]

What problem does this PR solve?

Issue Number: Close #5481

What is changed and how does it work?

The original TestWatchKeyspace attempts to flush the testSuite storage by manually calling TearDownSuite and then SetupSuite, which causes the testSuite to be unstable.

This PR makes TestWatchKeyspace compare expected and actual result using re.Contains instead of doing direct indexed comparison, thus making flushing the storage unnecessary.

Check List

Tests

• Integration test

Release note

none

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• lhy1024
• rleungx

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[AmoebaProtozoa]

/cc @rleungx

[codecov]

Codecov Report

Base: 75.62% // Head: 75.58% // Decreases project coverage by -0.03% ⚠️

Coverage data is based on head (74e9798) compared to base (5ca01a8).
Patch has no changes to coverable lines.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #5493      +/-   ##
==========================================
- Coverage   75.62%   75.58%   -0.04%     
==========================================
  Files         320      320              
  Lines       31622    31622              
==========================================
- Hits        23913    23901      -12     
- Misses       5645     5668      +23     
+ Partials     2064     2053      -11     

Flag	Coverage Δ
unittests	75.58% <ø> (-0.04%)	⬇️

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

Impacted Files	Coverage Δ
pkg/dashboard/keyvisual/input/core.go	0.00% <0.00%> (-33.34%)	⬇️
server/tso/local_allocator.go	71.62% <0.00%> (-6.76%)	⬇️
server/storage/kv/etcd_kv.go	79.71% <0.00%> (-5.80%)	⬇️
server/region_syncer/server.go	78.02% <0.00%> (-3.85%)	⬇️
server/schedule/hbstream/heartbeat_streams.go	71.71% <0.00%> (-3.04%)	⬇️
server/api/region.go	67.63% <0.00%> (-1.45%)	⬇️
server/schedule/region_scatterer.go	78.71% <0.00%> (-1.21%)	⬇️
tools/pd-ctl/pdctl/command/operator.go	66.66% <0.00%> (-1.15%)	⬇️
pkg/btree/btree.go	86.26% <0.00%> (-0.97%)	⬇️
server/schedulers/evict_leader.go	78.57% <0.00%> (-0.90%)	⬇️
... and 18 more

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[lhy1024]

/merge

[ti-chi-bot]

@lhy1024: It seems you want to merge this PR, I will help you trigger all the tests:

/run-all-tests

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[ti-chi-bot]

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

Commit hash: 947662e

[ti-chi-bot]

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

At the same time I will also trigger all tests for you:

/run-all-tests

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.