What problem does it solve? Tests that pass or fail unpredictably because they depend on real external services (HTTP APIs, DNS) or fixed real-time sleeps erode trust in the test suite and slow down CI. This Skill provides systematic detection and containment methods for these two flakiness sources. ## Core Features & Use Cases - External network containment: Detect real outbound communication by cutting the network and running repeated test iterations, then replace external calls with test doubles (MSW, stubs) that fix responses, including error cases like timeouts and 5xx. - Timer and sleep containment: Find fixed sleeps via grep, reproduce failures under CPU load, and replace them with fake timers (vi.useFakeTimers) or condition-based waiting (vi.waitFor, expect.poll). - Completion checklists: Each factor ships with verification criteria, such as network-cut runs passing 20 consecutive iterations and zero remaining fixed sleeps under load. - Use Case: A Vitest suite intermittently fails on CI. Use this Skill to block outbound network access, identify tests hitting real APIs, stub fetch responses, and convert setTimeout-based waits into condition polling until the suite is green across repeated runs. ## Quick Start Use the flakiness-external skill to find and fix the flaky tests in my Vitest suite that depend on real API calls and fixed sleeps.
