kotlin and ArgumentCaptor - IllegalStateException
I have a problem with capturing the Class argument via ArgumentCaptor. My test class looks like this:
@RunWith(RobolectricGradleTestRunner::class)
@Config(sdk = intArrayOf(21), constants = BuildConfig::class)
class MyViewModelTest {
@Mock
lateinit var activityHandlerMock: IActivityHandler;
@Captor
lateinit var classCaptor: ArgumentCaptor<Class<BaseActivity>>
@Captor
lateinit var booleanCaptor: ArgumentCaptor<Boolean>
private var objectUnderTest: MyViewModel? = null
@Before
fun setUp() {
initMocks(this)
...
objectUnderTest = MyViewModel(...)
}
@Test
fun thatNavigatesToAddListScreenOnAddClicked(){
//given
//when
objectUnderTest?.addNewList()
//then
verify(activityHandlerMock).navigateTo(classCaptor.capture(), booleanCaptor.capture())
var clazz = classCaptor.value
assertNotNull(clazz);
assertFalse(booleanCaptor.value);
}
}
When I run the test, following exception is thrown:
java.lang.IllegalStateException: classCaptor.capture() must not be null
Is it possible to use argument captors in kotlin?
=========
UPDATE 1:
Kotlin: 1.0.0-beta-4584
Mockito: 1.10.19
Robolectric: 3.0
=========
UPDATE 2:
Stacktrace:
java.lang.IllegalStateException: classCaptor.capture() must not be null
at com.example.view.model.ShoplistsViewModelTest.thatNavigatesToAddListScreenOnAddClicked(ShoplistsViewModelTest.kt:92)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26)
at org.robolectric.RobolectricTestRunner$2.evaluate(RobolectricTestRunner.java:251)
at org.robolectric.RobolectricTestRunner.runChild(RobolectricTestRunner.java:188)
at org.robolectric.RobolectricTestRunner.runChild(RobolectricTestRunner.java:54)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
at org.robolectric.RobolectricTestRunner$1.evaluate(RobolectricTestRunner.java:152)
at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:69)
at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:234)
at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:74)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:144)
From this blog
"Getting matchers to work with Kotlin can be a problem. If you have a method written in kotlin that does not take a nullable parameter then we cannot match with it using Mockito.any(). This is because it can return void and this is not assignable to a non-nullable parameter. If the method being matched is written in Java then I think that it will work as all Java objects are implicitly nullable."
A wrapper function is needed that returns ArgumentCaptor.capture()
as nullable type.
Add the following as a helper method to your test
fun <T> capture(argumentCaptor: ArgumentCaptor<T>): T = argumentCaptor.capture()
Please see, MockitoKotlinHelpers.kt provided by Google in the Android Architecture repo for reference. the capture
function provides a convenient way to call ArgumentCaptor.capture()
. Call
verify(activityHandlerMock).navigateTo(capture(classCaptor), capture(booleanCaptor))
Update: If the above solution does not work for you, please check Roberto Leinardi's solution in the comments below.
The return value of classCaptor.capture()
is null, but the signature of IActivityHandler#navigateTo(Class, Boolean)
does not allow a null argument.
The mockito-kotlin library provides supporting functions to solve this problem.
Code should be:
@Captor
lateinit var classCaptor: ArgumentCaptor<Class<BaseActivity>>
@Captor
lateinit var booleanCaptor: ArgumentCaptor<Boolean>
...
@Test
fun thatNavigatesToAddListScreenOnAddClicked(){
//given
//when
objectUnderTest?.addNewList()
//then
verify(activityHandlerMock).navigateTo(
com.nhaarman.mockitokotlin2.capture<Class<BaseActivity>>(classCaptor.capture()),
com.nhaarman.mockitokotlin2.capture<Boolean>(booleanCaptor.capture())
)
var clazzValue = classCaptor.value
assertNotNull(clazzValue);
val booleanValue = booleanCaptor.value
assertFalse(booleanValue);
}
OR
var classCaptor = com.nhaarman.mockitokotlin2.argumentCaptor<Class<BaseActivity>>()
var booleanCaptor = com.nhaarman.mockitokotlin2.argumentCaptor<Boolean>()
...
verify(activityHandlerMock).navigateTo(
classCaptor.capture(),
booleanCaptor.capture()
)
also in build.gradle add this:
testImplementation "com.nhaarman.mockitokotlin2:mockito-kotlin:2.2.0"
Use kotlin-mockito https://mvnrepository.com/artifact/com.nhaarman/mockito-kotlin/1.5.0 as dependency and sample code as written below :
argumentCaptor<Hotel>().apply {
verify(hotelSaveService).save(capture())
assertThat(allValues.size).isEqualTo(1)
assertThat(firstValue.name).isEqualTo("İstanbul Hotel")
assertThat(firstValue.totalRoomCount).isEqualTo(10000L)
assertThat(firstValue.freeRoomCount).isEqualTo(5000L)
}
As stated by CoolMind in the comment, you first need to add gradle import for Kotlin-Mockito and then shift all your imports to use this library. Your imports will now look like:
import com.nhaarman.mockitokotlin2.argumentCaptor
import com.nhaarman.mockitokotlin2.any
import com.nhaarman.mockitokotlin2.eq
import com.nhaarman.mockitokotlin2.isNull
import com.nhaarman.mockitokotlin2.mock
import com.nhaarman.mockitokotlin2.verify
Then your test class will be something like this:
val mArgumentCaptor = argumentCaptor<SignUpInteractor.Callback>()
@Test
fun signUp_success() {
val customer = Customer().apply {
name = "Test Name"
email = "[email protected]"
phone = "0123444456789"
phoneDdi = "+92"
phoneNumber = ""
countryCode = "92"
password = "123456"
}
mPresenter.signUp(customer)
verify(mView).showProgress()
verify(mInteractor).createAccount(any(), isNull(), mArgumentCaptor.capture())
}