testing-animations-deterministically

What problem does it solve?

This Skill solves flaky Jetpack Compose UI tests caused by indeterminate or time-based animations running differently on CI versus locally.

Core Features & Use Cases

• Make animation timing deterministic by disabling mainClock.autoAdvance and driving frames manually.
• Handle infinite/indeterminate animations safely so InfiniteAnimationPolicy does not fail your test with CancellationException.
• Avoid mid-animation test hangs and race conditions by mutating Compose state with runOnUiThread (not runOnIdle) while the clock is paused.
• Use test-clock waiting correctly with mainClock.advanceTimeUntil { ... } for state-observable conditions inside the paused-clock window.

Quick Start

Set up your Compose UI test by setting mainClock.autoAdvance = false before setContent, then call advanceTimeByFrame() once to kick off the animation and step it with advanceTimeBy(durationMillis) before asserting the intermediate UI state.