with JUnit (4), Is there an uncomplicated way to t...

# announcements

[iex]

with JUnit (4), Is there an uncomplicated way to test that a callback was called (ideally without mockito or any other 3d party)?
E.g. in Swift you can declare an "expectation" at the beginning of the test, call waitForExpectations(timeout: 5, handler: *nil*) at the end, and in the callback expectation.fullfill() to have the test wait for the callback

[Casey Brooks]

You’re probably best off running the test as a coroutine with runBlocking, which allows you to wrap the async call with suspendCancelableCoroutine and await for the result. Something like:

@Test
fun test1() = runBlocking {
    val underTest = ServiceUnderTest()
    val result = suspendCancellableCoroutine<String> { continuation ->
        underTest.makeCall { continuation.resume(it) }
    }

    assertEquals("expectedValue", result)
}

[elizarov]

It is simpler with a job:

val event = Job()
event.complete() // to fire it
event.await() // to await for it

[iex]

@elizarov should have mentioned that I'm using Android / JVM 1.6, sorry 😞

[iex]

@Casey Brooks any idea why this hangs? The "!!! logged: $foo" shows up in the console but not "!!! doesn't execute this"

@Test
fun testCallCallback() = runBlocking {
    val n = NativeApi()

    val result = suspendCancellableCoroutine<String> { continuation ->
        n.callCallback(object: Callback() {
            override fun log(foo: String) {
                println("!!! logged: $foo")
                continuation.resume(foo, onCancellation = {})
            }
        })
    }
    println("!!! doesn't execute this")
    assertEquals(result, "hi!")
}

[iex]

actually, it does show up 🤔

[iex]

the test actually is executed correctly and passes, but the green line stays in the middle and it shows a progress indicator, as if it was still running... any ideas?

[iex]

it completes after 2 minutes or so

[iex]

it seems mostly fixed by using runBlockingTest and adding a advanceTimeBy(120000) at the end

[iex]

(and adding a CoroutineTestRule)

[gildor]

should have mentioned that I’m using Android / JVM 1.6, sorry

But Job works fine on Android

[iex]

await appeared not to exist? Then I tried wait() and it showed an error with JVM 1.6. What am I missing?

[Animesh Sahu]

I think you need to include kotlinx.coroutines library

[gildor]

Yes, it's part of kotlinx.coroutines.
But for job you need .join(), not .await(), but if you want to return value from callback you can use CompletableDeferred() + .await()