I have a wrapper class for CoroutineDispatcher that I use so that for tests I can provide test dispa...

# coroutines

[eygraber]

I have a wrapper class for CoroutineDispatcher that I use so that for tests I can provide test dispatchers:

interface MyDispatchers {
  val main: CoroutineDispatcher
  val io: CoroutineDispatcher
  val computation: CoroutineDispatcher
  val unconfined: CoroutineDispatcher
}

Instead of using Dispatchers.* I use one of the properties from `MyDispatchers`(which are set to the corresponding Dispatchers.*)

Is this necessary, or does the coroutines test artifact have a construct that allows you to use Dispatchers.* and control them during a test?

[ephemient]

Dispatchers.Main can be set by test code: https://kotlin.github.io/kotlinx.coroutines/kotlinx-coroutines-test/kotlinx.coroutines.test/set-main.html

[ephemient]

the others can't - I'm not sure it ever makes sense to change Dispatchers.Unconfined, as it has some unique behavior

[eygraber]

So the correct approach would be to keep what I have, and for tests, set the Dispatchers to a TestCoroutineDispatcher (aside from Unconfined because of its behavior)?

Or am I better off using Dispatchers.* and rely on the behavior of runBlockingTest for time advancement, etc...

The reason I ask is because it's pretty clunky passing MyDispatchers around, but I don't want to not use it, and paint myself into a corner later on if I need a test dispatcher.

[ephemient]

my team has chosen to use our own Dispatchers singleton object, like the built in one but with IO settable

[eygraber]

Can you share some examples of the things you do when overriding IO?

[ephemient]

the only thing we override it to is the test dispatcher

[ephemient]

(which is customized to log uncaught exceptions and report them at the end of the test, but anyway)

[eygraber]

Ok thanks for the help