Determinism, goldens, and integration

Async determinism

Expose clocks, randomness, schedulers, transports, and storage through existing project seams. Await a named state or event. If progress may never complete, use a bounded loop or framework timeout that reports the missing condition. Cancel timers, streams, subscriptions, and pending work in teardown.

pumpAndSettle is suitable only when the UI is expected to settle. For repeating animations, polling, or intentionally live streams, advance a known duration or pump until an explicit observable condition.

Goldens

Stabilize fonts, locale, theme, surface size, pixel ratio, animation time, and fixtures. Store focused variants rather than one enormous application screenshot. A golden update is a review artifact: render the diff, explain the intended change, and reject unrelated pixel movement.

Integration

Seed independent data, reset durable state, and avoid ordering dependencies. Assert meaningful user milestones instead of implementation timing. Run the smallest supported device matrix that covers platform-specific behavior and report skipped targets explicitly.

Sources

• Flutter widget testing
• Flutter integration testing