Use when tests have race conditions, timing dependencies, or inconsistent pass/fail behavior - replaces arbitrary timeouts with condition polling to wait for actual state changes, eliminating flaky tests from timing guesses
clawd add obra/condition-based-waitingOverview
This skill eliminates flaky tests by replacing arbitrary timeouts with condition-based polling. Instead of guessing how long an operation takes, wait for the actual condition you care about.
The Problem
Flaky tests often use arbitrary delays like setTimeout(50) or sleep(100). These guesses work fine on fast machines but fail under load, in CI, or with parallel execution. Different computers and environments have different performance characteristics, making these timeouts unreliable.
The Solution
Wait for the actual condition you care about, not a guess about timing:
// Before: Guessing
await new Promise((r) => setTimeout(r, 50))
// After: Condition-based
await waitFor(() => result !== undefined)
When to Use
- Tests with arbitrary delays (setTimeout, sleep, time.sleep)
- Tests that fail inconsistently or under load
- Tests that timeout during parallel execution
- Waiting for async operations to complete
Real-World Impact
Applied to a debugging session:
- Fixed 15 flaky tests across 3 files
- Pass rate improved from 60% to 100%
- Execution time improved by 40%
- Eliminated race conditions entirely
This skill transforms unreliable tests into deterministic, fast-running tests that consistently pass.