Tag See all →

#flaky-tests

2 stories

Banner: tests passed alone and failed in the full suite because a session-scoped pytest fixture leaked state

Programming Languages Bug Report

Tests passed alone and failed in the full suite: a session-scoped pytest fixture leaked state

Lucas Moreau · Mar 30, 2026 · 7 min read

A handful of tests in our Python service failed only when the whole suite ran, and only in some orders. A session-scoped fixture returned a mutable settings object that one test modified. How we proved it with random ordering and bisection, and how fixture scopes, factories and monkeypatch keep tests isolated.

Banner: an end-to-end test timeline where fixed sleeps race against a page that loads at varying speeds

Web Development Bug Report

Flaky Playwright suite: hard sleeps, racing navigation and ambiguous selectors

Daniel Tran · Apr 10, 2025 · 9 min read

One CI run in eight failed somewhere in our checkout E2E suite, never in the same test twice. The causes were fixed sleeps, URL checks that raced navigation and text selectors that matched two buttons. Web-first assertions, role locators and traces fixed it.