how to stub kotlin map function | unittest

Question

i want to stub kotlin's map extension function in my unit test. couldn't find any proper solution on internet to do that.

ctually i have put empty blocks inside curly brackets but it seems like this is not the way that i should do.

here is what i have been trying so far:

whenever(trainWorkoutResult.exerciseSections.map {}).thenReturn(trainSections)

here is the error that i got:

no answer found for: 

    LegacyDataMapper(#4).mappingSectionsToRecordedExerciseDataModels(Mock for List, hashCode: 1199894489)

any idea?

Relevant: https://stackoverflow.com/questions/44382540/mocking-extension-function-in-kotlin — Tenfour04, Mar 27 '23 at 14:38
You cannot and should not. You can stub the function you pass _to_ `map`, but not `map` itself, and a good thing too. — Louis Wasserman, Mar 27 '23 at 17:28

score 0 · Answer 1 · answered Mar 28 '23 at 08:50

solved it like that:

 with(mockk<List<Section>>()) {
                every {
                    trainWorkoutResult.exerciseSections
                } returns (listOf(Section(12, "123", emptyList())))
            }

inspired by this question.

ps: i am using mockk library

how to stub kotlin map function | unittest

1 Answers1