reactivestate-core-test
Utilities for writing coroutine tests.
Unit tests with coroutines
The CoroutineTest base class provides some often useful helpers for working with coroutines.
class MyTest : CoroutineTest() {
// This works because MainScope/Dispatchers.Main is automatically set up correctly by CoroutineTest
val viewModel = MyViewModel()
// Let's use a mock to test the events emitted by MyViewModel
val events: MyEvents = mock()
@Before
fun setup() {
// You can access the TestCoroutineScope directly to launch some background processing.
// In this case, let's process MyViewModel's events.
testCoroutineScope.launch {
viewModel.eventNotifier.collect { events.it() }
}
}
@Test
fun someTest() = runTest {
viewModel.doSomething()
advanceUntilIdle()
verify(events).someEvent()
}
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This also sets up a global dispatchers variable which you can use in all of your code instead of passing a CoroutineDispatcher around as arguments:
// Use this instead of Dispatchers.IO. In unit tests this will automatically use
// the TestCoroutineDispatcher instead. Outside of unit tests it points to Dispatchers.IO.
// You can also define your own overrides if you want.
withContext(dispatchers.io) {
// do some IO
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If you can't derive from CoroutineTest directly (e.g. because you have some other base test class), you can alternatively use composition with the CoroutineTestRule:
class MyTest {
val rule = CoroutineTestRule()
@Test
fun someTest() = rule.runTest {
// ...
}
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