Stubbing returns null with named argument mixed ordering

I’m not sure whether it’s mockito-kotlin as it seems that something is wrong on boundary of kotlin/mockito, however it might be a thing that mockito-kotlin can solve somehow.

It seems like that using named arguments that are ordered in a different way compared to method signature breaks stubs so they return nulls only. Once I managed to get a class cast exception as Mockito was trying to cast my Arg2 into Arg underneath, however now I’m not able to reproduce it.

Here are couple of tests showing this behaviour

    @Test // failing
    fun `reverse order stub`() {
        val arg = Arg()
        val arg2 = Arg2()

        val pointFactory: PointFactory = mock()
        whenever(pointFactory.newInstance(y = any(), x = any())).thenReturn(mock())

        val result = pointFactory.newInstance(arg, arg2)

        Truth.assertThat(result).isNotNull()
    }

    @Test // failing
    fun `reverse order stub, reverse invocation`() {
        val arg = Arg()
        val arg2 = Arg2()

        val pointFactory: PointFactory = mock()
        whenever(pointFactory.newInstance(y = any(), x = any())).thenReturn(mock())

        val result = pointFactory.newInstance(y = arg2, x = arg)

        Truth.assertThat(result).isNotNull()
    }

    @Test
    fun `regular order stub, regular invocation`() {
        val arg = Arg()
        val arg2 = Arg2()

        val pointFactory: PointFactory = mock()
        whenever(pointFactory.newInstance(x = any(), y = any())).thenReturn(mock())

        val result = pointFactory.newInstance(arg, arg2)

        Truth.assertThat(result).isNotNull()
    }

    @Test
    fun `regular order stub, reverse invocation`() {
        val arg = Arg()
        val arg2 = Arg2()

        val pointFactory: PointFactory = mock()
        whenever(pointFactory.newInstance(x = any(), y = any())).thenReturn(mock())

        val result = pointFactory.newInstance(y = arg2, x = arg)

        Truth.assertThat(result).isNotNull()
    }

    class Arg
    class Arg2

    class Point

    class PointFactory {

        fun newInstance(x: Arg, y: Arg2): Point {
            return Point()
        }
    }

Also on mockito issue tracker: https://github.com/mockito/mockito/issues/1413

[StormeHawke]

We’re software engineers. If our job was easy anybody could do it 😉

[tianyanz]

Is there any plan to fix this?