What Really Makes Your Tests Flaky

Flaky tests. The bane of my existence. When I started unit testing, there was no such thing as a flaky test. Tests passed for the right reason, and they failed for the right reason. API tests? Not always. In this video, I walk through the real reason your tests are flaky — and it's not the tests. It's the assumptions baked into them. I break down four usual suspects: → State Pollution - your test created something and nobody cleaned it up → Order Dependency - your test only works because another test ran first → Concurrency - your test assumed it was alone in the system → External Factors - caching, feature flags, time of day, third-party services Each one hides a different assumption. Each one turns green into a coin flip. You can't kill flakiness completely. But you can reduce it — once you know what you're assuming. 🔗 REGISTER FOR THE WEBINAR — "Modern API Testing: Fighting Flakiness" June 3rd, 3PM CET / 9AM EDT. Free. We'll go through seven suspects, live examples, and a tool I built to surface assumptions in your test code. https://us02web.zoom.us/webinar/register/7817677801362/WN_Wo6ezTHfR3Smru0VRXxsSg 🚀 The API Testing Masterclass: The Strategist is coming later in 2026. Not like any API testing course out there. 👉 Join the waitlist → https://testingil.com/mc-api-testing-strategist Connect with TestinGil: 🌐 Website: https://www.testingil.com/ 💼 LinkedIn: https://www.linkedin.com/in/gilzilberfeld/ 🦋 BlueSky: https://bsky.app/profile/gilzilberfeld.bsky.social If you enjoyed this video, please: ✅ Like the video ✅ Subscribe to the channel ✅ Share it with someone who reruns their tests and calls it a fix #APITesting #SoftwareTesting #FlakyTests #TestAutomation #QualityEngineering