feat: Improve flaky tests and add error messages

[chrfwow]

Makes some tests more robust

[gemini-code-assist]

Summary of Changes

Hello @chrfwow, 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 focuses on improving the stability and diagnostic capabilities of existing tests. It addresses flakiness in a specific test by introducing more precise timing measurements and detailed error reporting. Additionally, it enhances the robustness of end-to-end tests by adopting a thread-safe data structure for event collection, ensuring reliable behavior in concurrent environments.

Highlights

• Improved Test Robustness: Enhanced the callingInitialize_wakesUpWaitingThread test in FlagdProviderSyncResourcesTest.java by replacing a simple boolean flag with a precise time measurement (AtomicLong waitTime). This change allows for more accurate assessment of the waiting duration and provides a detailed error message upon failure, making the test less flaky and easier to debug.
• Enhanced Concurrency for E2E Events: Switched the event collection mechanism in end-to-end tests from LinkedList to ConcurrentLinkedQueue in State.java and EventSteps.java. This change improves thread safety and performance for concurrent event handling, making the e2e tests more reliable in multi-threaded scenarios.

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[gemini-code-assist]

Code Review

This pull request improves test robustness by addressing potential concurrency issues and enhancing assertion messages. The change from LinkedList to ConcurrentLinkedQueue for handling events in E2E tests is a good move to prevent race conditions. The assertion message in FlagdProviderSyncResourcesTest is now more informative. I've added a couple of suggestions: one to improve test performance and readability by using a lazy-evaluated assertion message, and another to remove a redundant and potentially problematic re-initialization of a shared state field, which could itself introduce flakiness.

[gemini-code-assist]

The events field in the State class is already initialized where it's declared. Re-initializing it here in the EventSteps constructor is redundant and can introduce flakiness. If other step definitions in the same scenario modify the events list before this constructor is called, those changes will be lost. It's best to remove this line and rely on the single initialization in the State class.

[gemini-code-assist]

For better performance and readability, it's a good practice to use a lambda for the assertion message in JUnit 5. This enables lazy evaluation, meaning the message string is only constructed if the assertion fails. This avoids unnecessary string concatenation in passing tests.

Suggested change

	Assertions.assertTrue(
	waitTime.get() < MAX_TIME_TOLERANCE * 2,
	"Wakeup should be almost instant, but took " + waitTime.get()
	+ " ms, which is more than the max of"
	+ (MAX_TIME_TOLERANCE * 2) + " ms");
	Assertions.assertTrue(
	waitTime.get() < MAX_TIME_TOLERANCE * 2,
	() -> "Wakeup should be almost instant, but took " + waitTime.get()
	+ " ms, which is more than the max of"
	+ (MAX_TIME_TOLERANCE * 2) + " ms");