WorkManager provides APIs for testing Worker
,
ListenableWorker
, and the
ListenableWorker
variants
(CoroutineWorker
and RxWorker
).
Testing Workers
Let’s say we have a Worker
which looks like this:
Kotlin
class SleepWorker(context: Context, parameters: WorkerParameters) : Worker(context, parameters) { override fun doWork(): Result { // Sleep on a background thread. Thread.sleep(1000) return Result.success() } }
Java
public class SleepWorker extends Worker { public SleepWorker( @NonNull Context context, @NonNull WorkerParameters workerParameters) { super(context, workerParameters); } @NonNull @Override public Result doWork() { try { Thread.sleep(1000); } catch (InterruptedException ignore) { return Result.success(); } } }
To test this Worker
, you can use
TestWorkerBuilder
. This
builder helps build instances of Worker
that can be used for the purpose of
testing business logic.
Kotlin
// Kotlin code uses the TestWorkerBuilder extension to build // the Worker @RunWith(AndroidJUnit4::class) class SleepWorkerTest { private lateinit var context: Context private lateinit var executor: Executor @Before fun setUp() { context = ApplicationProvider.getApplicationContext() executor = Executors.newSingleThreadExecutor() } @Test fun testSleepWorker() { val worker = TestWorkerBuilder<SleepWorker>( context = context, executor = executor ).build() val result = worker.doWork() assertThat(result, `is`(Result.success())) } }
Java
@RunWith(AndroidJUnit4.class) public class SleepWorkerJavaTest { private Context context; private Executor executor; @Before public void setUp() { context = ApplicationProvider.getApplicationContext(); executor = Executors.newSingleThreadExecutor(); } @Test public void testSleepWorker() { SleepWorker worker = (SleepWorker) TestWorkerBuilder.from(context, SleepWorker.class, executor) .build(); Result result = worker.doWork(); assertThat(result, is(Result.success())); } }
TestWorkerBuilder
can also be used to set tags, such as inputData
or
runAttemptCount
, so that you can verify worker state in isolation. Consider
an example in which SleepWorker
takes in a sleep duration as input data
rather than it being a constant defined in the worker:
Kotlin
class SleepWorker(context: Context, parameters: WorkerParameters) : Worker(context, parameters) { override fun doWork(): Result { // Sleep on a background thread. val sleepDuration = inputData.getLong(SLEEP_DURATION, 1000) Thread.sleep(sleepDuration) return Result.success() } companion object { const val SLEEP_DURATION = "SLEEP_DURATION" } }
Java
public class SleepWorker extends Worker { public static final String SLEEP_DURATION = "SLEEP_DURATION"; public SleepWorker( @NonNull Context context, @NonNull WorkerParameters workerParameters) { super(context, workerParameters); } @NonNull @Override public Result doWork() { try { long duration = getInputData().getLong(SLEEP_DURATION, 1000); Thread.sleep(duration); } catch (InterruptedException ignore) { return Result.success(); } } }
In SleepWorkerTest
, you can provide that input data to your
TestWorkerBuilder
to satisfy the needs of SleepWorker
.
Kotlin
// Kotlin code uses the TestWorkerBuilder extension to build // the Worker @RunWith(AndroidJUnit4::class) class SleepWorkerTest { private lateinit var context: Context private lateinit var executor: Executor @Before fun setUp() { context = ApplicationProvider.getApplicationContext() executor = Executors.newSingleThreadExecutor() } @Test fun testSleepWorker() { val worker = TestWorkerBuilder<SleepWorker>( context = context, executor = executor, inputData = workDataOf("SLEEP_DURATION" to 1000L) ).build() val result = worker.doWork() assertThat(result, `is`(Result.success())) } }
Java
@RunWith(AndroidJUnit4.class) public class SleepWorkerJavaTest { private Context context; private Executor executor; @Before public void setUp() { context = ApplicationProvider.getApplicationContext(); executor = Executors.newSingleThreadExecutor(); } @Test public void testSleepWorker() { Data inputData = new Data.Builder() .putLong("SLEEP_DURATION", 1000L) .build(); SleepWorker worker = (SleepWorker) TestWorkerBuilder.from(context, SleepWorker.class, executor) .setInputData(inputData) .build(); Result result = worker.doWork(); assertThat(result, is(Result.success())); } }
For more details on the TestWorkerBuilder
API, see the reference page for
TestListenableWorkerBuilder
,
the superclass of TestWorkerBuilder
.
Testing ListenableWorker and its variants
To test a ListenableWorker
or its
variants (CoroutineWorker
and RxWorker
), use
TestListenableWorkerBuilder
.
The main difference between TestWorkerBuilder
and a
TestListenableWorkerBuilder
is that TestWorkerBuilder
lets you specify the background Executor
used to
run the Worker
, whereas TestListenableWorkerBuilder
relies on the
threading logic of the ListenableWorker
implementation.
For example, suppose we need to test a CoroutineWorker
which looks like this:
class SleepWorker(context: Context, parameters: WorkerParameters) :
CoroutineWorker(context, parameters) {
override suspend fun doWork(): Result {
delay(1000L) // milliseconds
return Result.success()
}
}
To test SleepWorker
, we first create an instance of the Worker using
TestListenableWorkerBuilder
and then call its doWork
function within a
coroutine.
@RunWith(AndroidJUnit4::class)
class SleepWorkerTest {
private lateinit var context: Context
@Before
fun setUp() {
context = ApplicationProvider.getApplicationContext()
}
@Test
fun testSleepWorker() {
val worker = TestListenableWorkerBuilder<SleepWorker>(context).build()
runBlocking {
val result = worker.doWork()
assertThat(result, `is`(Result.success()))
}
}
}
runBlocking
makes sense as a coroutine builder for your tests so that any code
that would execute asynchronously is instead run in parallel.
Testing an RxWorker
implementation is similar to testing CoroutineWorker
, as
TestListenableWorkerBuilder
can handle any subclass of ListenableWorker
.
Consider a version of SleepWorker
that uses RxJava instead of coroutines.
Kotlin
class SleepWorker( context: Context, parameters: WorkerParameters ) : RxWorker(context, parameters) { override fun createWork(): Single<Result> { return Single.just(Result.success()) .delay(1000L, TimeUnit.MILLISECONDS) } }
Java
public class SleepWorker extends RxWorker { public SleepWorker(@NonNull Context appContext, @NonNull WorkerParameters workerParams) { super(appContext, workerParams); } @NonNull @Override public Single<Result> createWork() { return Single.just(Result.success()) .delay(1000L, TimeUnit.MILLISECONDS); } }
A version of SleepWorkerTest
that tests an RxWorker
may look similar to the
version that tested a CoroutineWorker
. You use the same
TestListenableWorkerBuilder
but now call into RxWorker
’s createWork
function. createWork
returns a Single
that you can use to verify the
behavior of your worker. TestListenableWorkerBuilder
handles any threading
complexities and executes your worker code in parallel.
Kotlin
@RunWith(AndroidJUnit4::class) class SleepWorkerTest { private lateinit var context: Context @Before fun setUp() { context = ApplicationProvider.getApplicationContext() } @Test fun testSleepWorker() { val worker = TestListenableWorkerBuilder<SleepWorker>(context).build() worker.createWork().subscribe { result -> assertThat(result, `is`(Result.success())) } } }
Java
@RunWith(AndroidJUnit4.class) public class SleepWorkerTest { private Context context; @Before public void setUp() { context = ApplicationProvider.getApplicationContext(); } @Test public void testSleepWorker() { SleepWorker worker = TestListenableWorkerBuilder.from(context, SleepWorker.class) .build(); worker.createWork().subscribe(result -> assertThat(result, is(Result.success()))); } }