kotlin and ArgumentCaptor - IllegalStateException

Question

I have a problem with capturing the Class argument via ArgumentCaptor. My test class looks like this:

@RunWith(RobolectricGradleTestRunner::class)
@Config(sd         


        

Answer 1

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"

Answer 2

You can write a wrapper over argument captor

class CaptorWrapper<T:Any>(private val captor:ArgumentCaptor<T>, private val obj:T){
    fun capture():T{
        captor.capture()
        return obj
    }

    fun captor():ArgumentCaptor<T>{
        return captor
    }
}

Answer 3

Another approach:

/**
 * Use instead of ArgumentMatcher.argThat(matcher: ArgumentMatcher<T>)
 */
fun <T> safeArgThat(matcher: ArgumentMatcher<T>): T {
    ThreadSafeMockingProgress.mockingProgress().argumentMatcherStorage
        .reportMatcher(matcher)
    return uninitialized()
}

@Suppress("UNCHECKED_CAST")
private fun <T> uninitialized(): T = null as T

Usage:

verify(spiedElement, times(1)).method(
    safeArgThat(
        CustomMatcher()
    )
)

Answer 4

For some, there is a file, MockitoKotlinHelpers.kt provided by Google in the Android Architecture repo. It provides a convenient way to call capture.. just 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.

Answer 5

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 = "test@example.com"
        phone = "0123444456789"
        phoneDdi = "+92"
        phoneNumber = ""
        countryCode = "92"
        password = "123456"
    }
    mPresenter.signUp(customer)
    verify(mView).showProgress()
    verify(mInteractor).createAccount(any(), isNull(), mArgumentCaptor.capture())
}

Answer 6

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)
}