test(performance-timer): reduce flakiness of tests involving actual sleeps#4890
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test(performance-timer): reduce flakiness of tests involving actual sleeps#4890
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Pull Request Overview
This PR addresses flaky test failures in performance timer tests by replacing imprecise time assertions with more robust timing verification that accounts for CI environment variability.
- Replaces
closeToassertions withatLeastchecks for minimum sleep duration - Adds timestamp tracking around performance measurements for precise bounds validation
- Includes debug logging to help diagnose timing issues in CI environments
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straker
approved these changes
Sep 24, 2025
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Fixes some flaky test cases that were failing as often as not in the
test_firefoxjob, where we were seeing in practice thatawait sleep(100)was frequently taking much longer than 100ms to actually complete. This updates the tests to avoid using "closeTo" in assertions of how long a sleep lasts, in favor ofatLeast+ verifying nearness to whatperformance.now()reports.I verified this in 10x runs against firefox locally (where it exhibited the same failure before the fix and no failure after the fix) + 3x runs in CI: