ProduceCallbackWrapperTest.kt

import kotlinx.coroutines.experimental.*
import kotlinx.coroutines.experimental.channels.*
import org.junit.Test
import kotlin.coroutines.experimental.CoroutineContext

data class Intent(val action: String)

class BroadcastSender() {

}

interface BroadcastReceiver {
	fun onReceive(intent: Intent)
}

class Context() {
	var broadcastReceiver: BroadcastReceiver? = null

	fun send(action: String) { broadcastReceiver?.onReceive(Intent(action)) }

	fun registerReceiver(broadcastReceiver: BroadcastReceiver) {
		this.broadcastReceiver = broadcastReceiver
	}

	fun unregisterReceiver(broadcastReceiver: BroadcastReceiver) {
		this.broadcastReceiver = null
	}
}

suspend fun awaitCancel(): Nothing = suspendCancellableCoroutine {  }

suspend fun registerBroadcastReceiver(context: Context): ReceiveChannel<Intent> =
		produce<Intent>(capacity = Channel.UNLIMITED) {
			var broadcastReceiver:BroadcastReceiver? = null
			try {
				broadcastReceiver = object : BroadcastReceiver {
					override fun onReceive(intent: Intent) {
						sendBlocking(intent)
					}
				}.also {
					context.registerReceiver(it)
					awaitCancel()
				}
			} finally {
				context.unregisterReceiver(broadcastReceiver!!)
			}
		}

class CoroutineTest {

	@Test
	fun testProduceCallbackWrapper() = runBlocking {
		val context = Context()
		val channel = registerBroadcastReceiver(context)
		val result = async(coroutineContext) { channel.any {
			if (it.action == "hello") { channel.cancel(); true } else false
		} }

		context.send("hello")
		yield()

		assert(result.await())
	}

	@Test
	fun testProduceCallbackWrapperWithFor() = runBlocking {
		val context = Context()
		val channel = registerBroadcastReceiver(context)
		var result = false

		launch(coroutineContext) {
			for (currIntent in channel) {
				if(currIntent.action == "hello") {
					result =  true
					channel.cancel()
				}
			}
		}

		context.send("something1")
		context.send("something2")
		context.send("something3")
		context.send("something4")
		context.send("hello")
		yield()

		assert(result)
	}
}