fix: flaky metric test

[alkatrivedi]

No description provided.

[gemini-code-assist]

Summary of Changes

Hello @alkatrivedi, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request addresses a flakiness issue in a metric test by refining an assertion logic. The change ensures that the test accurately reflects the expected relationship between attempt and operation latencies, improving the reliability of the test suite and preventing intermittent failures.

Highlights

• Metric Test Fix: Corrected an assertion in test/metrics/metrics.ts to compare attemptLatency against operationLatency instead of MIN_LATENCY, resolving a flaky test scenario by aligning the assertion with the test's intent.

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[gemini-code-assist]

Code Review

This pull request addresses a flaky test by correctly asserting that attemptLatency should be approximately equal to operationLatency when there is only a single attempt. The change is correct and improves test stability.

I've identified a similar issue in another test within the same file. The test 'should have correct latency values in metrics except AFE when AFE Server timing is disabled' in test/metrics/metrics.ts has the same logic on line 713 that was just fixed. It still compares attemptLatency with MIN_LATENCY. To prevent future flakiness, this should also be updated to compare against operationLatency.

[surbhigarg92]

There are 2 test cases which uses this MIN_LATENCY, both needs to be corrected

[alkatrivedi]

done

[surbhigarg92]

This doesn't seem right to me, Unit test should not take this long, ideally elapsed time should always be closer to totalOperationLatency.
In your testing what behavior do you see, totalOperationLatency is bigger or elapsed time ?
Can you add logs and see what all operationLatency value is coming for different methods vs the total latency.

We need to see for this test case if createSession is called when database.run is called or before that ? Maybe that is why we see this discrepancy now with mux session.

[surbhigarg92]

Check what all "resourceMetrics" contains, is it having createSession or not and how it differs from regular sessio

[alkatrivedi]

In your testing what behavior do you see, totalOperationLatency is bigger or elapsed time ?

elapsedTime is more than the totalOperationLatency. Ref - https://github.com/googleapis/nodejs-spanner/actions/runs/19628416394/job/56202180201