I am referring this talk by *`Márton Braun`* . <ht...

# coroutines

[Abhimanyu]

I am referring this talk by Márton Braun .

https://youtu.be/nKCsIHWircA?t=1124▾

Does this mean async is always preferred over launch even when fire and forget works for my functionality?

https://kotlinlang.slack.com/files/UPQU769PU/F07Q66B5WAG/image.png▾

https://kotlinlang.slack.com/files/UPQU769PU/F07QGBQLUUR/image.png▾

[Sam]

I think I'd agree with the general point he's making, that starting async work without giving callers a way to wait for it isn't very helpful. But there's no reason to return Deferred<Unit>; the Job returned by launch will do just as well

[Sam]

The timestamp is about 18:42 for anyone else looking at the video

[Abhimanyu]

I am trying to test a method in my view model which has viewModelScope.launch { } .
When using StandardTestDispatcher , I am not sure how to launch the coroutines.

[blakelee]

I always understood it as async is for if you care about the return value as well as the job and launch is if you don't care about the value

[Abhimanyu]

Hi Blake,

Yes, I refer to the same guidelines when deciding between launch or async. That's why I found this situation a bit confusing.

I'm trying to understand if there's anything else I should consider when making the choice.

[blakelee]

I just watched the portion relating to your question. I'm in agreement with Sam. If you need to wait for it in a test, just return the Job from the launch

[Abhimanyu]

In my case, I am launching coroutines that collect continuously.
So, even if I do return viewModelScope.launch {} , I am not sure how that helps.
This is the actual issue - https://kotlinlang.slack.com/archives/C1CFAFJSK/p1727888646418719.

[blakelee]

I see what you're saying. I was looking at a previous example of mine where I was using UnconfinedTestDispatcher and I was able to launch stuff with the backgroundScope . Would it make sense to break up the two different launches into separate functions so that you can use call them for tests?

[Abhimanyu]

Okay, in my actual code, they are in separate methods, but they are private .

I would prefer not to expose them just for testing.

[Abhimanyu]

Also, it is not possible in all places to split multiple continuous flow collectors.