WorkManager provides a work-testing artifact which helps with testing of your workers.
Setup
To use the work-testing artifact, add it as an androidTestImplementation dependency in build.gradle.
Groovy
dependencies { def work_version = "2.5.0" ... // optional - Test helpers androidTestImplementation "androidx.work:work-testing:$work_version" }
Kotlin
dependencies { val work_version = "2.4.0" ... // optional - Test helpers androidTestImplementation("androidx.work:work-testing:$work_version") }
For more information on adding dependencies, look at the Declaring dependencies section in the WorkManager release notes.
Concepts
work-testing provides a special implementation of WorkManager for test mode, which is initialized using WorkManagerTestInitHelper.
The work-testing artifact also provides a SynchronousExecutor which makes it easier to write tests in a synchronous manner, without having to deal with multiple threads, locks, or latches.
Here is an example on how to use all these classes together.
Kotlin
@RunWith(AndroidJUnit4::class) class BasicInstrumentationTest { @Before fun setup() { val context = InstrumentationRegistry.getTargetContext() val config = Configuration.Builder() .setMinimumLoggingLevel(Log.DEBUG) .setExecutor(SynchronousExecutor()) .build() // Initialize WorkManager for instrumentation tests. WorkManagerTestInitHelper.initializeTestWorkManager(context, config) } }
Java
@RunWith(AndroidJUnit4.class) public class BasicInstrumentationTest { @Before public void setup() { Context context = InstrumentationRegistry.getTargetContext(); Configuration config = new Configuration.Builder() .setMinimumLoggingLevel(Log.DEBUG) .setExecutor(new SynchronousExecutor()) .build(); // Initialize WorkManager for instrumentation tests. WorkManagerTestInitHelper.initializeTestWorkManager( context, config); } }
Structuring Tests
Now that WorkManager has been initialized in test mode, you are ready to test your workers.
Let’s say you have an EchoWorker which expects some inputData, and simply copies (echoes) its input to outputData.
Kotlin
class EchoWorker(context: Context, parameters: WorkerParameters) : Worker(context, parameters) { override fun doWork(): Result { return when(inputData.size()) { 0 -> Result.failure() else -> Result.success(inputData) } } }
Java
public class EchoWorker extends Worker { public EchoWorker(Context context, WorkerParameters parameters) { super(context, parameters); } @NonNull @Override public Result doWork() { Data input = getInputData(); if (input.size() == 0) { return Result.failure(); } else { return Result.success(input); } } }
Basic Tests
Below is an Android Instrumentation test that tests EchoWorker. The main takeaway here is that testing EchoWorker in test mode is very similar to how you would use EchoWorker in a real application.
Kotlin
@Test @Throws(Exception::class) fun testSimpleEchoWorker() { // Define input data val input = workDataOf(KEY_1 to 1, KEY_2 to 2) // Create request val request = OneTimeWorkRequestBuilder<EchoWorker>() .setInputData(input) .build() val workManager = WorkManager.getInstance(applicationContext) // Enqueue and wait for result. This also runs the Worker synchronously // because we are using a SynchronousExecutor. workManager.enqueue(request).result.get() // Get WorkInfo and outputData val workInfo = workManager.getWorkInfoById(request.id).get() val outputData = workInfo.outputData // Assert assertThat(workInfo.state, `is`(WorkInfo.State.SUCCEEDED)) assertThat(outputData, `is`(input)) }
Java
@Test public void testSimpleEchoWorker() throws Exception { // Define input data Data input = new Data.Builder() .put(KEY_1, 1) .put(KEY_2, 2) .build(); // Create request OneTimeWorkRequest request = new OneTimeWorkRequest.Builder(EchoWorker.class) .setInputData(input) .build(); WorkManager workManager = WorkManager.getInstance(getApplicationContext()); // Enqueue and wait for result. This also runs the Worker synchronously // because we are using a SynchronousExecutor. workManager.enqueue(request).getResult().get(); // Get WorkInfo and outputData WorkInfo workInfo = workManager.getWorkInfoById(request.getId()).get(); Data outputData = workInfo.getOutputData(); // Assert assertThat(workInfo.getState(), is(WorkInfo.State.SUCCEEDED)); assertThat(outputData, is(input)); }
Let’s write another test which makes sure that when EchoWorker gets no input data, the expected Result is a Result.failure().
Kotlin
@Test @Throws(Exception::class) fun testEchoWorkerNoInput() { // Create request val request = OneTimeWorkRequestBuilder<EchoWorker>() .build() val workManager = WorkManager.getInstance(applicationContext) // Enqueue and wait for result. This also runs the Worker synchronously // because we are using a SynchronousExecutor. workManager.enqueue(request).result.get() // Get WorkInfo val workInfo = workManager.getWorkInfoById(request.id).get() // Assert assertThat(workInfo.state, `is`(WorkInfo.State.FAILED)) }
Java
@Test public void testEchoWorkerNoInput() throws Exception { // Create request OneTimeWorkRequest request = new OneTimeWorkRequest.Builder(EchoWorker.class) .build(); WorkManager workManager = WorkManager.getInstance(getApplicationContext()); // Enqueue and wait for result. This also runs the Worker synchronously // because we are using a SynchronousExecutor. workManager.enqueue(request).getResult().get(); // Get WorkInfo WorkInfo workInfo = workManager.getWorkInfoById(request.getId()).get(); // Assert assertThat(workInfo.getState(), is(WorkInfo.State.FAILED)); }
Simulate constraints, delays, and periodic work
WorkManagerTestInitHelper provides you with an instance of TestDriver which can be used to simulate initial delay, conditions where constraints are met for ListenableWorker instances, and, intervals for PeriodicWorkRequest instances.
Test Initial Delays
Workers can have initial delays. To test EchoWorker with an initialDelay, rather than having to wait for the initialDelay in your test, you can use the TestDriver to mark the work request’s initial delay as met using setInitialDelayMet.
Kotlin
@Test @Throws(Exception::class) fun testWithInitialDelay() { // Define input data val input = workDataOf(KEY_1 to 1, KEY_2 to 2) // Create request val request = OneTimeWorkRequestBuilder<EchoWorker>() .setInputData(input) .setInitialDelay(10, TimeUnit.SECONDS) .build() val workManager = WorkManager.getInstance(getApplicationContext()) // Get the TestDriver val testDriver = WorkManagerTestInitHelper.getTestDriver() // Enqueue workManager.enqueue(request).result.get() // Tells the WorkManager test framework that initial delays are now met. testDriver.setInitialDelayMet(request.id) // Get WorkInfo and outputData val workInfo = workManager.getWorkInfoById(request.id).get() val outputData = workInfo.outputData // Assert assertThat(workInfo.state, `is`(WorkInfo.State.SUCCEEDED)) assertThat(outputData, `is`(input)) }
Java
@Test public void testWithInitialDelay() throws Exception { // Define input data Data input = new Data.Builder() .put(KEY_1, 1) .put(KEY_2, 2) .build(); // Create request OneTimeWorkRequest request = new OneTimeWorkRequest.Builder(EchoWorker.class) .setInputData(input) .setInitialDelay(10, TimeUnit.SECONDS) .build(); WorkManager workManager = WorkManager.getInstance(myContext); // Get the TestDriver TestDriver testDriver = WorkManagerTestInitHelper.getTestDriver(); // Enqueue workManager.enqueue(request).getResult().get(); // Tells the WorkManager test framework that initial delays are now met. testDriver.setInitialDelayMet(request.getId()); // Get WorkInfo and outputData WorkInfo workInfo = workManager.getWorkInfoById(request.getId()).get(); Data outputData = workInfo.getOutputData(); // Assert assertThat(workInfo.getState(), is(WorkInfo.State.SUCCEEDED)); assertThat(outputData, is(input)); }
Testing Constraints
TestDriver can also be used to mark constraints as met using setAllConstraintsMet. Here is an example on how you can test a Worker with constraints.
Kotlin
@Test @Throws(Exception::class) fun testWithConstraints() { // Define input data val input = workDataOf(KEY_1 to 1, KEY_2 to 2) val constraints = Constraints.Builder() .setRequiredNetworkType(NetworkType.CONNECTED) .build() // Create request val request = OneTimeWorkRequestBuilder<EchoWorker>() .setInputData(input) .setConstraints(constraints) .build() val workManager = WorkManager.getInstance(myContext) val testDriver = WorkManagerTestInitHelper.getTestDriver() // Enqueue workManager.enqueue(request).result.get() // Tells the testing framework that all constraints are met. testDriver.setAllConstraintsMet(request.id) // Get WorkInfo and outputData val workInfo = workManager.getWorkInfoById(request.id).get() val outputData = workInfo.outputData // Assert assertThat(workInfo.state, `is`(WorkInfo.State.SUCCEEDED)) assertThat(outputData, `is`(input)) }
Java
@Test public void testWithConstraints() throws Exception { // Define input data Data input = new Data.Builder() .put(KEY_1, 1) .put(KEY_2, 2) .build(); // Define constraints Constraints constraints = new Constraints.Builder() .setRequiresDeviceIdle(true) .build(); // Create request OneTimeWorkRequest request = new OneTimeWorkRequest.Builder(EchoWorker.class) .setInputData(input) .setConstraints(constraints) .build(); WorkManager workManager = WorkManager.getInstance(myContext); TestDriver testDriver = WorkManagerTestInitHelper.getTestDriver(); // Enqueue workManager.enqueue(request).getResult().get(); // Tells the testing framework that all constraints are met. testDriver.setAllConstraintsMet(request.getId()); // Get WorkInfo and outputData WorkInfo workInfo = workManager.getWorkInfoById(request.getId()).get(); Data outputData = workInfo.getOutputData(); // Assert assertThat(workInfo.getState(), is(WorkInfo.State.SUCCEEDED)); assertThat(outputData, is(input)); }
Testing Periodic Work
The TestDriver also exposes a setPeriodDelayMet which can be used to indicate that an interval is complete. Here is an example of setPeriodDelayMet being used.
Kotlin
@Test @Throws(Exception::class) fun testPeriodicWork() { // Define input data val input = workDataOf(KEY_1 to 1, KEY_2 to 2) // Create request val request = PeriodicWorkRequestBuilder<EchoWorker>(15, MINUTES) .setInputData(input) .build() val workManager = WorkManager.getInstance(myContext) val testDriver = WorkManagerTestInitHelper.getTestDriver() // Enqueue and wait for result. workManager.enqueue(request).result.get() // Tells the testing framework the period delay is met testDriver.setPeriodDelayMet(request.id) // Get WorkInfo and outputData val workInfo = workManager.getWorkInfoById(request.id).get() // Assert assertThat(workInfo.state, `is`(WorkInfo.State.ENQUEUED)) }
Java
@Test public void testPeriodicWork() throws Exception { // Define input data Data input = new Data.Builder() .put(KEY_1, 1) .put(KEY_2, 2) .build(); // Create request PeriodicWorkRequest request = new PeriodicWorkRequest.Builder(EchoWorker.class, 15, MINUTES) .setInputData(input) .build(); WorkManager workManager = WorkManager.getInstance(myContext); TestDriver testDriver = WorkManagerTestInitHelper.getTestDriver(); // Enqueue and wait for result. workManager.enqueue(request).getResult().get(); // Tells the testing framework the period delay is met testDriver.setPeriodDelayMet(request.getId()); // Get WorkInfo and outputData WorkInfo workInfo = workManager.getWorkInfoById(request.getId()).get(); // Assert assertThat(workInfo.getState(), is(WorkInfo.State.ENQUEUED)); }