Pick the right test type per Clean Architecture layer the canonical Android way — domain/UseCase/ repository as JVM unit tests (JUnit5 via the mannodermaus android-junit5 plugin + MockK with coEvery/ coVerify), ViewModel StateFlow emission sequences with Turbine's test {} + awaitItem(), and Composables as instrumented JUnit4 tests using createComposeRule() + onNodeWithText(). Enforces runTest (NOT runBlockingTest), Dispatchers.setMain for viewModelScope, and useUnmergedTree for granular semantics assertions. Use when writing tests for any Android/Compose layer.
