onInputPicked does not reach Ready on the calling thread. It hops twice --
withContext(pickDispatcher) { InputQuery.describe(...) } and then the probe
-- and pickDispatcher defaults to Dispatchers.IO, a real background thread
Compose's idling knows nothing about. So deliver() returned with the state
still Idle, and asserting immediately was a race the test usually won.
It lost five times on CI in one day, on PRs whose diffs were instrumented
tests and documentation and could not reach it. Two of those failures came
alongside #125's deadlock and could be argued as fallout; three did not.
waitUntil polls through waitForIdle, draining the main looper each time, so
it sees the recomposition the IO hop eventually posts back.
Injecting the dispatcher would be better and is not available here.
pickDispatcher is a constructor parameter precisely so a test can pin it,
but this test composes the real ConverterScreen, which resolves its own
ViewModel through viewModel() -- the seam is one layer below the launcher
edge this class exists to cover, and reaching for it would mean not testing
that edge.
The evidence is the mutation rather than the repetition count, per the note
#218 left: transposing the two launcher callbacks at ConverterScreen.kt:70
and :83 -- the exact defect this test guards -- still fails it, so the wait
did not make it vacuous. A transposed callback leaves the screen in Idle
forever and it fails on the timeout with the meaning it had before.
Supporting evidence, eight consecutive green runs of the class.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
JMR-devandClaude Opus 5