Espresso

Tools to provide Espresso functionality for coroutines.

If an IdlingDispatcherProvider is registered with the IdlingRegistry, Espresso will wait for all associated coroutines to leave the active state before performing any assertions.

Coroutines which are in a suspended state (such as a Job "observing" a Flow for updates) do not prevent Espresso from performing assertions.

class IdlingCoroutineScopeRuleWithLifecycleSample {

  // Retrieve the DispatcherProvider from a dependency graph,
  // so that the same one is used throughout the codebase.
  val customDispatcherProvider = testAppComponent.customDispatcherProvider

  @JvmField
  @Rule
  val idlingRule = IdlingDispatcherProviderRule {
    IdlingDispatcherProvider(customDispatcherProvider)
  }

  /**
  * If you don't provide CoroutineScopes to your lifecycle components via a dependency injection framework,
  * you need to use the `dispatch-android-lifecycle-extensions` and `dispatch-android-viewmodel` artifacts
  * to ensure that the same `IdlingDispatcherProvider` is used.
  */
  @Before
  fun setUp() {
    LifecycleScopeFactory.set {
      MainImmediateCoroutineScope(customDispatcherProvider)
    }
    ViewModelScopeFactory.set {
      MainImmediateCoroutineScope(customDispatcherProvider)
    }
  }

  @Test
  fun testThings() = runBlocking {

    // Now any CoroutineScope which uses the DispatcherProvider
    // in TestAppComponent will sync its "idle" state with Espresso

  }

}

Types

Name	Description
IdlingDispatcherProviderRule	JUnit 4 Rule which automatically registers an IdlingDispatcherProvider with the IdlingRegistry
IdlingDispatcher	A CoroutineDispatcher which tracks each dispatched coroutine using a CountingIdlingResource. All actual dispatches are delegated to a provided CoroutineDispatcher.
IdlingDispatcherProvider	A special DispatcherProvider which guarantees that each of its properties is an IdlingDispatcher
IdlingCoroutineScope	A special CoroutineScope which guarantees a property of an IdlingDispatcherProvider

IdlingCoroutineScopes

Marker Interface	Factory Function	Description
DefaultIdlingCoroutineScope	DefaultIdlingCoroutineScope	A IdlingCoroutineScope with a CoroutineDispatcher of default.
IOIdlingCoroutineScope	IOIdlingCoroutineScope	A IdlingCoroutineScope with a CoroutineDispatcher of io.
MainIdlingCoroutineScope	MainIdlingCoroutineScope	A IdlingCoroutineScope with a CoroutineDispatcher of main.
MainImmediateIdlingCoroutineScope	MainImmediateIdlingCoroutineScope	A IdlingCoroutineScope with a CoroutineDispatcher of mainImmediate.
UnconfinedIdlingCoroutineScope	UnconfinedIdlingCoroutineScope	A IdlingCoroutineScope with a CoroutineDispatcher of unconfined.

Minimum Gradle Config

Add to your module's build.gradle.kts:

repositories {
  mavenCentral()
}

dependencies {

  // core
  implementation("org.jetbrains.kotlinx:kotlinx-coroutines-core:1.5.2")
  implementation("org.jetbrains.kotlinx:kotlinx-coroutines-android:1.5.2")
  implementation("com.rickbusarow.dispatch:dispatch-core:1.0.0-beta10-SNAPSHOT")

  androidTestImplementation("com.rickbusarow.dispatch:dispatch-android-espresso:1.0.0-beta10-SNAPSHOT")

  // android
  androidTestImplementation("androidx.test:runner:1.3.0")
  androidTestImplementation("androidx.test.espresso:espresso-core:3.3.0")
}