Riddle number 6 does not check for parallelism

Hey,

There is a small problem with riddle number 6 and it is up to you guys how you want to solve it. In the task description there is mentioned that

Execute both [first] and [second] Single’s in parallel…

however you solution works sequentially. Thats because there are no schedulers running on mentioned Singles which means everything executes on main thread. Test is passing because it is not really checking for parallelism. If you would want to do that you could

val first = Single.timer(5, SECONDS, rxRule)
        .map { 10 }
        .doOnSubscribe { subscribeCounter.incrementAndGet() }

val second = Single.timer(3, SECONDS, rxRule)
        .map { 5 }
        .doOnSubscribe { subscribeCounter.incrementAndGet() }

// rest of the test goes here...

rxRule.advanceTimeBy(4, SECONDS)

// check if second already finished and the first one did not
first.test().assertNotComplete()
second.test().assertComplete()

You get the idea. So if the intention was to check for parallelism you need to adjust solution. If solution is good then you need to adjust the description.

[vanniktech]

I don’t quite understand the problem.

RxRule is having a Scheduler that will run. The essential part is that subscribe is called eagerly. Which is asserted with assertEmpty() & assertThat(subscribeCounter.get()).isEqualTo(2) // We want to subscribe immediately.

[lwasyl]

@vanniktech took me a while to find time for this, here is my suggestion. I believe not providing a scheduler and not changing the comment is the way to go for this to still be a riddle 😉 Let me know what you think