[WIP] Flaky test in :agent:instrumentation:micrometer-1.0

[Copilot]

Analyzing flaky test in agent:instrumentation:micrometer-1.0 module.

Analysis Plan

• Examine MicrometerTest.java for potential flakiness sources
• Identify resource leaks in shouldCaptureLongTaskTimer test
• Add proper test cleanup between tests (@AfterEach)
• Fix LongTaskTimer test to use finite sleep and proper cleanup
• Add explicit timeouts to await() calls for CI stability
• Test the changes to ensure flakiness is resolved

Key Issues Found

1. Resource Leaks: shouldCaptureLongTaskTimer creates ExecutorService with threads that sleep indefinitely and never shuts down
2. No Test Isolation: Static delegate accumulates measurements across tests without cleanup
3. Missing Timeouts: await().until() calls lack explicit timeouts which can hang in CI

Minimal Fix Strategy

• Add @AfterEach method to reset delegate between tests
• Fix LongTaskTimer test to use controlled sleep duration and proper resource cleanup
• Add timeouts to await() calls for robustness

Fixes #4253.

---

💬 Share your feedback on Copilot coding agent for the chance to win a $200 gift card! Click here to start the survey.