Bug: Mocking varargs

[UlfHesselbarth]

In Mockito there is anyVararg() but mockk does not have this.
Consider the following example:

interface Foo {
   fun foo(vararg args: String, otherArg: String)
   fun foo(args: List<String>, otherArg: String)
}

@Test
fun varargTest() {
   val mock = mockk<Foo>()
   // this works as expected, matching the List<String> version
   every { mock.foo(args = any<List<String>>(), otherArg = any()) } just Runs

   // this does not work, compiles but fails at runtime with:
   // io.mockk.MockKException: Failed matching mocking signature for
   // Foo(#1).foo([529c407ddf5619f7], -4522a650db14c274)
   // left matchers: [any()]
   every { mock.foo(args = *arrayOf(any()), otherArg = any()) } just Runs
}

Is there another way to mock the vararg version of foo?

[oleksiyp]

Look like issue is appearing when using interface or abstract class. When using simple class it is passing:

    class Foo {
        fun foo(vararg args: String, otherArg: String) {

        }
        fun foo(args: List<String>, otherArg: String) {
            
        }
    }

I've checked underlying reflection call and seems Kotlin is just not returning correct value. So it is a Kotlin reflection API bug

[oleksiyp]

After additional checking, it appears that pure interface is working. So it is related to metadata propagation i.e. while using interface MockK needs to create a proxy subclass and Kotlin metadata is not copied to that subclass.

[oleksiyp]

So yes this because of subclassing. issue52 branch fixes it but makes builds 25% slower. This is something to solve additionally.

[gildor]

@oleksiyp I cannot verify vararg, method with vararg always fail verification (except verify(exactly = 0), just because of it never called)
Can you confirm, that this is related to this issue or I do something wrong?

[oleksiyp]

Very probable that this is related.
Fix/workaround is making MockK slow, so it was not merged.
Some caching to be applied.
Or maybe other ways to fix it.

Right now(one/two weeks) I'm quite free for doing MockK improvements/fixes but focused on Android instrumentation test which is a big feature. Will get back to such not very big things after releasing it.

I desperately need good co-author :-)

[oleksiyp]

In version 1.8 it should be fixed. Please check

[oleksiyp]

Seems it was fixed, reopen if it is not

[darrenhaken]

What's the fix for this @oleksiyp ? I'm using 1.9 and having trouble mocking a varargs.

[oleksiyp]

In version 1.8 it should be fixed. Please check

Please report as a new bug

[darrenhaken]

@oleksiyp new issue opened at #224