condition-based-waiting_skill

Overview

This skill provides practical, reusable patterns to eliminate race conditions and timing-related flakiness in tests. It focuses on replacing brittle fixed sleeps with condition-based waiting, and offers helpers for Redis, WebSockets, databases, file I/O, and service health checks. The goal is predictable tests that wait for actual readiness rather than arbitrary delays.

How this skill works

The skill supplies a small set of async wait-for-condition primitives and higher-level helpers that poll until a predicate becomes true or a timeout elapses. It integrates with test fixtures and retry decorators so you can wait for Redis pings, WebSocket handshakes, database records, file writes, or external HTTP health checks. Logging, environment-aware timeouts, and exponential backoff patterns make waits observable and configurable for local and CI environments.

When to use it

• Intermittent test failures that pass on retry
• Async tests with Redis connection timing issues
• WebSocket connection handshakes and message ordering problems
• Database transactions or eventual consistency delays
• File system operations that complete asynchronously

Best practices

• Replace fixed time.sleep calls with condition-based waiting and explicit timeouts
• Tune timeouts per environment (local vs CI) and expose them via env vars
• Log wait progress and reasons for timeouts to make failures actionable
• Always close and clean up connections in fixtures to avoid cascading flakiness
• Avoid infinite loops—use sensible poll intervals and overall timeouts

Example use cases

• A pytest fixture that waits for Redis, Postgres, and an HTTP service before running integration tests
• An async WebSocket test client that waits for handshake messages and content before asserting
• A database helper that waits for a specific record to appear after a background job
• A file-watcher test that waits for a file to exist and reach a minimum size or contain expected content
• A retry decorator for flaky API calls with exponential backoff in test helpers