I have a unit test that calls a method with a `launch(UI)` in it, but I'm getting the following mess...

# coroutines

[Joe]

I have a unit test that calls a method with a launch(UI) in it, but I'm getting the following message

java.lang.NoClassDefFoundError: Could not initialize class kotlinx.coroutines.experimental.android.HandlerContextKt

[julioyg]

@Joe you might have figured it out by now but you, could inject in the class you launch the coroutine from a class wrapping up the coroutinesContexts, that way you can mock that class for your tests, something like:

class MyClass(cc: coroutineContexts) {
  fun myMethod() {
   launch(cc.ui) {
   }
  }
}

interface CoroutineContexts {
  val ui: CourotineContext
}

class Test {
  private val mockedCoroutines = object: CoroutineContexts {
  override val ui = Unconfined
}

  private val sut = MyClass(mockedCoroutines)
  fun test() {
    //test
  }
}

hope it helps

[Joe]

Yeah, I've looked at that, and if that's necessary, that's fine. I was just surprised the class doesn't seem to exist in the unit tests at all. 😞