Flaky Test

ELI5 — The Vibe Check

A flaky test is a test that sometimes passes and sometimes fails for no clear reason — even when nothing changed. It's unreliable, like a friend who sometimes shows up and sometimes doesn't. Flaky tests destroy trust in your test suite because you never know if a failure is real.

Real Talk

A flaky test is a non-deterministic test that produces inconsistent results without code changes. Common causes include timing issues (async/await problems), test order dependencies, shared mutable state, random data, and network calls. Flaky tests erode confidence in CI pipelines.

When You'll Hear This

"Ignore that failure — it's a known flaky test." / "We have a quarantine suite for flaky tests while we investigate root causes."