CODEWITHSUNDEEP
androidunit-testingjunitkotlin-coroutinesmockk
DJ-DOO
DJ-DOO

Reputation: 4780

Mock throwing of Exception with Android Coroutines

I am introducing coroutines to an android app I am working. There is lots of legacy but I am now adding some new networking code and using coroutines for it.

EDIT Updating to add the whole test

coEvery { service.getAddress(any(), any(), any()) } coAnswers { throw Exception("Test Exception") }
val subject = repository.getAddress(123, "en", null)

coVerify(exactly = 1) { service.getAddress(any(), any(), any())}

So the line coEvery { service.getAddress(any(), any(), any()) } coAnswers { throw Exception("Test Exception") } in the test on it's own doesn't cause an issue. It falls down when adding val subject = repository.getAddress(123, "en", null)

EDIT 2 TO INCLUDE REPO Here is the repo:

class AddressRepository (
    val addressRestService: AddressRestService,
    val dispatcher: CoroutineDispatcher
){
    suspend fun getAddress(
        wlid: Int,
        locale: String?,
        googleAddressObject: GeoResponse?
    ) : AddressForm = withContext(dispatcher) {
             addressRestService.getAddress(wlid, locale, googleAddressObject)
    }
}

I am using clean architecture and I am trying to test my repository. I am using the Mockk lib and I am trying to test a failure.

Below is a snippet:

coEvery {
    service.getAddress(123, "en", null)
} throw Exception()

When running the above I get test failure with the following stack trace:

java.lang.Exception
    at **.*******.data.repository.AddressRepositoryTest$when getAddress is called, returns false$1.invokeSuspend(AddressRepositoryTest.kt:52)
    at **.*******.data.repository.AddressRepositoryTest$when getAddress is called, returns false$1.invoke(AddressRepositoryTest.kt)
    at kotlinx.coroutines.test.TestBuildersKt$runBlockingTest$deferred$1.invokeSuspend(TestBuilders.kt:50)
    at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:33)
    at kotlinx.coroutines.DispatchedTask.run(DispatchedTask.kt:106)
    at kotlinx.coroutines.test.TestCoroutineDispatcher.dispatch(TestCoroutineDispatcher.kt:50)
    at kotlinx.coroutines.internal.DispatchedContinuationKt.resumeCancellableWith(DispatchedContinuation.kt:322)
    at kotlinx.coroutines.intrinsics.CancellableKt.startCoroutineCancellable(Cancellable.kt:30)
    at kotlinx.coroutines.intrinsics.CancellableKt.startCoroutineCancellable$default(Cancellable.kt:25)
    at kotlinx.coroutines.CoroutineStart.invoke(CoroutineStart.kt:110)
    at kotlinx.coroutines.AbstractCoroutine.start(AbstractCoroutine.kt:126)
    at kotlinx.coroutines.BuildersKt__Builders_commonKt.async(Builders.common.kt:91)
    at kotlinx.coroutines.BuildersKt.async(Unknown Source)
    at kotlinx.coroutines.BuildersKt__Builders_commonKt.async$default(Builders.common.kt:82)
    at kotlinx.coroutines.BuildersKt.async$default(Unknown Source)
    at kotlinx.coroutines.test.TestBuildersKt.runBlockingTest(TestBuilders.kt:49)
    at kotlinx.coroutines.test.TestBuildersKt.runBlockingTest(TestBuilders.kt:73)
    at at **.*******.data.repository.AddressRepositoryTest$when getAddress is called, returns false(AddressRepositoryTest.kt:49)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.base/java.lang.reflect.Method.invoke(Method.java:566)
    at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:59)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:56)
    at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
    at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26)
    at org.junit.rules.TestWatcher$1.evaluate(TestWatcher.java:61)
    at org.junit.runners.ParentRunner$3.evaluate(ParentRunner.java:306)
    at org.junit.runners.BlockJUnit4ClassRunner$1.evaluate(BlockJUnit4ClassRunner.java:100)
    at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:366)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:103)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:63)
    at org.junit.runners.ParentRunner$4.run(ParentRunner.java:331)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:79)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:329)
    at org.junit.runners.ParentRunner.access$100(ParentRunner.java:66)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:293)
    at org.junit.runners.ParentRunner$3.evaluate(ParentRunner.java:306)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:413)
    at org.gradle.api.internal.tasks.testing.junit.JUnitTestClassExecutor.runTestClass(JUnitTestClassExecutor.java:110)
    at org.gradle.api.internal.tasks.testing.junit.JUnitTestClassExecutor.execute(JUnitTestClassExecutor.java:58)
    at org.gradle.api.internal.tasks.testing.junit.JUnitTestClassExecutor.execute(JUnitTestClassExecutor.java:38)
    at org.gradle.api.internal.tasks.testing.junit.AbstractJUnitTestClassProcessor.processTestClass(AbstractJUnitTestClassProcessor.java:62)
    at org.gradle.api.internal.tasks.testing.SuiteTestClassProcessor.processTestClass(SuiteTestClassProcessor.java:51)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.base/java.lang.reflect.Method.invoke(Method.java:566)
    at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:36)
    at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:24)
    at org.gradle.internal.dispatch.ContextClassLoaderDispatch.dispatch(ContextClassLoaderDispatch.java:33)
    at org.gradle.internal.dispatch.ProxyDispatchAdapter$DispatchingInvocationHandler.invoke(ProxyDispatchAdapter.java:94)
    at com.sun.proxy.$Proxy5.processTestClass(Unknown Source)
    at org.gradle.api.internal.tasks.testing.worker.TestWorker.processTestClass(TestWorker.java:119)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.base/java.lang.reflect.Method.invoke(Method.java:566)
    at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:36)
    at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:24)
    at org.gradle.internal.remote.internal.hub.MessageHubBackedObjectConnection$DispatchWrapper.dispatch(MessageHubBackedObjectConnection.java:182)
    at org.gradle.internal.remote.internal.hub.MessageHubBackedObjectConnection$DispatchWrapper.dispatch(MessageHubBackedObjectConnection.java:164)
    at org.gradle.internal.remote.internal.hub.MessageHub$Handler.run(MessageHub.java:414)
    at org.gradle.internal.concurrent.ExecutorPolicy$CatchAndRecordFailures.onExecute(ExecutorPolicy.java:64)
    at org.gradle.internal.concurrent.ManagedExecutorImpl$1.run(ManagedExecutorImpl.java:48)
    at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
    at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
    at org.gradle.internal.concurrent.ThreadFactoryImpl$ManagedThreadRunnable.run(ThreadFactoryImpl.java:56)
    at java.base/java.lang.Thread.run(Thread.java:829)

I have tried different variations e.g.

coEvery {
    service.getAddress(123, "en", null)
}.coAnswers {
    throw Exception()
}

When running the above I get a test failure with the following stack trace:

java.lang.Exception
    at **.****.******.data.repository.AddressRepositoryTest$when getAddress is called, returns false$1$2.invokeSuspend(AddressRepositoryTest.kt:53)
    at **.****.******.data.repository.AddressRepositoryTest$when getAddress is called, returns false$1$2.invoke(AddressRepositoryTest.kt)
    at io.mockk.MockKStubScope$coAnswers$1.invokeSuspend(API.kt:2112)
    at io.mockk.MockKStubScope$coAnswers$1.invoke(API.kt)
    at io.mockk.CoFunctionAnswer$answer$1.invokeSuspend(Answers.kt:33)
    at io.mockk.CoFunctionAnswer$answer$1.invoke(Answers.kt)
    at io.mockk.JvmCoroutineCall.callCoroutine(InternalPlatformDsl.kt:212)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.base/java.lang.reflect.Method.invoke(Method.java:566)
    at io.mockk.JvmCoroutineCall.callWithContinuation(InternalPlatformDsl.kt:217)
    at io.mockk.CoFunctionAnswer.answer(Answers.kt:34)
    at io.mockk.impl.stub.AnswerAnsweringOpportunity.answer(AnswerAnsweringOpportunity.kt:14)
    at io.mockk.impl.stub.MockKStub.answer(MockKStub.kt:54)
    at io.mockk.impl.recording.states.AnsweringState.call(AnsweringState.kt:16)
    at io.mockk.impl.recording.CommonCallRecorder.call(CommonCallRecorder.kt:53)
    at io.mockk.impl.stub.MockKStub.handleInvocation(MockKStub.kt:263)
    at io.mockk.impl.instantiation.JvmMockFactoryHelper$mockHandler$1.invocation(JvmMockFactoryHelper.kt:25)
    at io.mockk.proxy.jvm.advice.Interceptor.call(Interceptor.kt:20)
    at io.mockk.proxy.jvm.advice.BaseAdvice.handle(BaseAdvice.kt:42)
    at io.mockk.proxy.jvm.advice.jvm.JvmMockKProxyInterceptor.interceptNoSuper(JvmMockKProxyInterceptor.java:45)
    at **.****.******.data.api.AddressRestService$Subclass0.getAddress(Unknown Source)
    at **.****.******.data.repository.AddressRepository$getAddress$2.invokeSuspend(AddressRepository.kt:18)
    at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:33)
    at kotlinx.coroutines.DispatchedTask.run(DispatchedTask.kt:106)
    at kotlinx.coroutines.test.TestCoroutineDispatcher.dispatch(TestCoroutineDispatcher.kt:50)
    at kotlinx.coroutines.test.internal.TestMainDispatcher.dispatch(MainTestDispatcher.kt:35)
    at kotlinx.coroutines.internal.DispatchedContinuationKt.resumeCancellableWith(DispatchedContinuation.kt:322)
    at kotlinx.coroutines.intrinsics.CancellableKt.startCoroutineCancellable(Cancellable.kt:30)
    at kotlinx.coroutines.intrinsics.CancellableKt.startCoroutineCancellable$default(Cancellable.kt:25)
    at kotlinx.coroutines.BuildersKt__Builders_commonKt.withContext(Builders.common.kt:170)
    at kotlinx.coroutines.BuildersKt.withContext(Unknown Source)
    at **.****.******.data.repository.AddressRepository.getAddress(AddressRepository.kt:17)
    at **.****.******.data.repository.AddressRepositoryTest$when getAddress is called, returns false$1.invokeSuspend(AddressRepositoryTest.kt:56)
    at **.****.******.data.repository.AddressRepositoryTest$when getAddress is called, returns false$1.invoke(AddressRepositoryTest.kt)
    at kotlinx.coroutines.test.TestBuildersKt$runBlockingTest$deferred$1.invokeSuspend(TestBuilders.kt:50)
    at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:33)
    at kotlinx.coroutines.DispatchedTask.run(DispatchedTask.kt:106)
    at kotlinx.coroutines.test.TestCoroutineDispatcher.dispatch(TestCoroutineDispatcher.kt:50)
    at kotlinx.coroutines.internal.DispatchedContinuationKt.resumeCancellableWith(DispatchedContinuation.kt:322)
    at kotlinx.coroutines.intrinsics.CancellableKt.startCoroutineCancellable(Cancellable.kt:30)
    at kotlinx.coroutines.intrinsics.CancellableKt.startCoroutineCancellable$default(Cancellable.kt:25)
    at kotlinx.coroutines.CoroutineStart.invoke(CoroutineStart.kt:110)
    at kotlinx.coroutines.AbstractCoroutine.start(AbstractCoroutine.kt:126)
    at kotlinx.coroutines.BuildersKt__Builders_commonKt.async(Builders.common.kt:91)
    at kotlinx.coroutines.BuildersKt.async(Unknown Source)
    at kotlinx.coroutines.BuildersKt__Builders_commonKt.async$default(Builders.common.kt:82)
    at kotlinx.coroutines.BuildersKt.async$default(Unknown Source)
    at kotlinx.coroutines.test.TestBuildersKt.runBlockingTest(TestBuilders.kt:49)
    at kotlinx.coroutines.test.TestBuildersKt.runBlockingTest(TestBuilders.kt:73)
    at **.****.******.data.repository.AddressRepositoryTest.when getAddress is called, returns false(AddressRepositoryTest.kt:49)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.base/java.lang.reflect.Method.invoke(Method.java:566)
    at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:59)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:56)
    at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
    at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26)
    at org.junit.rules.TestWatcher$1.evaluate(TestWatcher.java:61)
    at org.junit.runners.ParentRunner$3.evaluate(ParentRunner.java:306)
    at org.junit.runners.BlockJUnit4ClassRunner$1.evaluate(BlockJUnit4ClassRunner.java:100)
    at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:366)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:103)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:63)
    at org.junit.runners.ParentRunner$4.run(ParentRunner.java:331)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:79)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:329)
    at org.junit.runners.ParentRunner.access$100(ParentRunner.java:66)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:293)
    at org.junit.runners.ParentRunner$3.evaluate(ParentRunner.java:306)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:413)
    at org.gradle.api.internal.tasks.testing.junit.JUnitTestClassExecutor.runTestClass(JUnitTestClassExecutor.java:110)
    at org.gradle.api.internal.tasks.testing.junit.JUnitTestClassExecutor.execute(JUnitTestClassExecutor.java:58)
    at org.gradle.api.internal.tasks.testing.junit.JUnitTestClassExecutor.execute(JUnitTestClassExecutor.java:38)
    at org.gradle.api.internal.tasks.testing.junit.AbstractJUnitTestClassProcessor.processTestClass(AbstractJUnitTestClassProcessor.java:62)
    at org.gradle.api.internal.tasks.testing.SuiteTestClassProcessor.processTestClass(SuiteTestClassProcessor.java:51)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.base/java.lang.reflect.Method.invoke(Method.java:566)
    at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:36)
    at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:24)
    at org.gradle.internal.dispatch.ContextClassLoaderDispatch.dispatch(ContextClassLoaderDispatch.java:33)
    at org.gradle.internal.dispatch.ProxyDispatchAdapter$DispatchingInvocationHandler.invoke(ProxyDispatchAdapter.java:94)
    at com.sun.proxy.$Proxy5.processTestClass(Unknown Source)
    at org.gradle.api.internal.tasks.testing.worker.TestWorker.processTestClass(TestWorker.java:119)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.base/java.lang.reflect.Method.invoke(Method.java:566)
    at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:36)
    at org.gradle.internal.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:24)
    at org.gradle.internal.remote.internal.hub.MessageHubBackedObjectConnection$DispatchWrapper.dispatch(MessageHubBackedObjectConnection.java:182)
    at org.gradle.internal.remote.internal.hub.MessageHubBackedObjectConnection$DispatchWrapper.dispatch(MessageHubBackedObjectConnection.java:164)
    at org.gradle.internal.remote.internal.hub.MessageHub$Handler.run(MessageHub.java:414)
    at org.gradle.internal.concurrent.ExecutorPolicy$CatchAndRecordFailures.onExecute(ExecutorPolicy.java:64)
    at org.gradle.internal.concurrent.ManagedExecutorImpl$1.run(ManagedExecutorImpl.java:48)
    at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
    at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
    at org.gradle.internal.concurrent.ThreadFactoryImpl$ManagedThreadRunnable.run(ThreadFactoryImpl.java:56)
    at java.base/java.lang.Thread.run(Thread.java:829)

I would very much appreciate if anyone could point out where I'm going wrong.. if it is possible to mock throwing an exception with coroutines. Any tips appreciated

Upvotes: 2

Views: 6350

Answers (1)

Sergio
Sergio

Reputation: 30715

You can try to use JUnit Jupiter library, it allows to test throwing Exceptions by using assertThrows method. For example if you want to test that service.getAddress() function throws some Exception under certain conditions you can test it like the following:

assertThrows<Exception> { service.getAddress(123, "en", null) }

This assertion checks whether getAddress throws Exception exception. You can replace Exception with another type you want to test.

If you want to throw an Exception you can use throws infix function:

coEvery { service.getAddress(123, "en", null) } throws NullPointerException("Error occurred")

I guess the error you get is happening due to incorrect return value. Please try to return AddressForm object instead of throwing an Exception:

coEvery { service.getAddress(any(), any(), any()) } returns AddressForm(...)

Upvotes: 2

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