FakeImageLoader.kt

class FakeImageLoader : ImageLoader {

  val requestSet = mutableSetOf<Request>()
  
  override fun load(request: LoadRequest): RequestDisposable {
    // Always call onStart before onSuccess.
    requestSet.add(request)
    request.target?.onStart(drawable)
    request.target?.onSuccess(drawable)
    return disposable
  }

  override suspend fun get(request: GetRequest): Drawable {
    requestSet.add(request)
    return drawable
  }
  
  //...
}