Hello, I have a function that uses generic that I would like to mock using mockito. ```abstract clas...

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[Pablo Schmid]

Hello, I have a function that uses generic that I would like to mock using mockito.

abstract class MyClass<T>(){
    abstract fun blocking(): T

fun <R> execute(run: (T)->R, onError: ((e: Throwable)->R)? = null): R {
        return runCatching { run(blocking()) }.getOrElse{ e -> onError?.let { it(e) } ?: throw e}
}
}

internal class MyClassImpl(): MyClass<String>() {
    override fun blocking(): String {
        return "something"
    }
}

I would like to mock the execute function in MyClassImpl that extends MyClass
I usually mock functions as follows but it's not compiling as it can't infer the types

private val myVariable = mock<MyClassImpl>().also {
        whenever(it.execute(any(), anyOrNull()).thenReturn(any())
    }

Really appreciate the help.

[mkrussel]

First i don't think you should be passing any() into thenReturn. The mock needs to return a specific value.

Then I think you need to specify the version of execute you are trying to mock.

mock<MyClassImpl>().also {
        whenever(it.execute<String>(any(), anyOrNull()).thenReturn("Expected Return Value")
    }

This would unfortunately return the String even if execute is called for a different generic.

[mkrussel]

I would also probably avoid mocking this class. By mocking execute you are mocking away the use of all the client code that is being passed into execute. That seems like you are then skipping a lot of code in the unit under test.

Would seem better instead to mock the blocking function and let execute do its thing.

[Pablo Schmid]

the problem with that is that blocking and execute are part of the same mocked class, so I need to mock execute too

[mkrussel]

You could do spy instead of a mock. I also think there is a way to configure Mockito to call the real method for methods that you don't mock, but I haven't played with that in a long time.

[Pablo Schmid]

Spy along with mocking blocking works! Thanks!