[router] Fix Flaky test_circuit_breaker_opens_and_recovers

[XinyueZhang369]

Motivation

Fix flaky test test_circuit_breaker_opens_and_recovers.
Sometimes the worker takes a bit longer to start. So when test hits the server, it receives 503 due to there's no available worker instead of circuit breaker is open. Then the test expects to receive 200 when worker starts and returns 500 for first 3 requests.

Modifications

Modify the test to wait to receive 500 first and then expect to receive 503, to ensure that test starts to check if circuit breaker is open after the worker is actually started.

Run the test for 500 times, didn't see any failure

Accuracy Tests

Benchmarking and Profiling

Checklist

• Format your code according to the Format code with pre-commit.
• Add unit tests according to the Run and add unit tests.
• Update documentation according to Write documentations.
• Provide accuracy and speed benchmark results according to Test the accuracy and Benchmark the speed.

[gemini-code-assist]

Summary of Changes

Hello @XinyueZhang369, 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 resolves a persistent flakiness issue in an integration test related to the circuit breaker mechanism. The core problem stemmed from the test sometimes attempting to verify circuit breaker behavior before the underlying worker was fully initialized. The changes introduce a robust waiting mechanism within the test, ensuring that the worker is ready to process requests before the circuit breaker's state is evaluated, thereby enhancing the reliability and accuracy of the test suite.

Highlights

• Flaky Test Fix: Addressed the flakiness in test_circuit_breaker_opens_and_recovers by ensuring the test waits for the worker to be fully operational before proceeding with circuit breaker checks.
• Test Logic Enhancement: Modified the test to first explicitly wait for a 500 status code (indicating the worker has started) and assert that any prior responses are 503 (service unavailable), preventing premature circuit breaker checks.
• Improved Reliability: The updated test logic ensures that the circuit breaker test accurately reflects the intended scenario, eliminating failures caused by worker startup delays.

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[gemini-code-assist]

Code Review

This pull request effectively addresses a flaky test by introducing a wait mechanism to ensure the worker is in the correct state before the test assertions are made. The logic is sound and makes the test more robust. I have one suggestion to refactor the implementation to be more idiomatic and concise by using a for...else pattern, which improves readability.

[CatherineSue]

Wait for CI