testing-flows-with-turbine

What problem does it solve?

This Skill prevents Flow-based tests from hanging when asserting emissions from hot streams like StateFlow and SharedFlow by providing a one-at-a-time, cancellation-safe assertion workflow.

Core Features & Use Cases

• Assert ordered emissions without toList(): Use flow.test { ... } / testIn(...) to await items, completion, or errors while ensuring no unconsumed events remain.
• Correctly handle hot vs cold Flow behavior: Avoid waiting for completion on hot flows and instead use cancel() or cancelAndIgnoreRemainingEvents() to end the test deterministically.
• Support multi-flow assertions: Use turbineScope and testIn to interleave assertions across multiple flows in the same test.
• Also verify non-Flow callbacks: Use the standalone Turbine<T>() channel to capture listener/callback invocations with the same awaitItem()-style vocabulary.

Example use case

You have a ViewModel exposing uiState: StateFlow<UiState> and events: SharedFlow<Event> and you need to assert the initial seed value, the subsequent loading and success states, and a one-shot event in a single run without the test stalling.

Quick Start

Ask the AI to show how to write a runTest using vm.uiState.test { ... } that asserts the StateFlow seed, awaits the next two emissions, and finishes with cancelAndIgnoreRemainingEvents() to avoid hanging.