barrier-concurrency-testing

Instead of setTimeout (flaky) or sleep (slow), use barriers to pause execution at exact interleave points. The test controls when each concurrent operation proceeds, making race condition tests deterministic and reproducible on every run.

When to use: Testing concurrent operations, flush conflicts, parallel mutations, race windows between read and write, lock contention scenarios, any code where timing affects correctness.

When not to use: Sequential-only code, simple unit tests, UI components, read-only operations, code with no concurrency concerns.

使用障碍和延迟承诺进行确定性竞争条件测试。用可重现的交错控制替换基于 setTimeout 的片状计时测试。 来源：apankov1/quality-engineering。