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

Came here after the kotlin-Mockito library didn't help. I created a solution using reflection. It is a function which extracts the argument provided to the mocked-object earlier:

fun  getTheArgOfUsedFunctionInMockObject(mockedObject: Any, function: (T) -> S, clsOfArgument: Class): T{
    val argCaptor= ArgumentCaptor.forClass(clsOfArgument)
    val ver = verify(mockedObject)
    argCaptor.capture()
    ver.javaClass.methods.first { it.name == function.reflect()!!.name }.invoke(ver, uninitialized())
    return argCaptor.value
}
private fun  uninitialized(): T = null as T

Usage: (Say I have mocked my repository and tested a viewModel. After calling the viewModel's "update()" method with a MenuObject object, I want to make sure that the MenuObject actually called upon the repository's "updateMenuObject()" method:

viewModel.update(menuObjectToUpdate)
val arg = getTheArgOfUsedFunctionInMockObject(mockedRepo, mockedRepo::updateMenuObject, MenuObject::class.java)
assertEquals(menuObjectToUpdate, arg)