CODEWITHSUNDEEP
javascalamockito
Sydney
Sydney

Reputation: 45

How can I mock a Void return type in Scala with Mockito?

I have a scala project with a Java dependency. I want to execute some code when a call is made to a java method that returns Void (specifically, I want to complete a future when this method is called). Is there any way to do this? The following compiles but throws an exception at runtime:

  val startLF = SettableFuture.create[Unit]()

  when(mockConsumer.start).thenAnswer(new Answer[Void]() {
    override def answer(invocationOnMock: InvocationOnMock): Void = {
      startLF.set()
      Void.TYPE.newInstance()
    }
  })

Thanks!

Upvotes: 0

Views: 1339

Answers (2)

Chris Martin
Chris Martin

Reputation: 30756

You could add an implicit Unit -> Void conversion:

import scala.language.implicitConversions
implicit def unitToVoid(u: Unit): Void = null

Then anything that returns Unit can be used in a place that expects Void, e.g.:

def foo: Void = println("")

Upvotes: -1

Ben Reich
Ben Reich

Reputation: 16324

It seems that you can ascribe null as Void, e.g.

def foo: Void = null

So in your example, you can replace Void.TYPE.newInstance() with null or null: Void to be clearer.

Upvotes: 2

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