Expose waitForCompletion for overriding

[armanbilge]

This is used to support timeouts for tests.

munit/munit/shared/src/main/scala/munit/FunSuite.scala

Lines 49 to 51 in 166698e

	def munitTimeout: Duration = new FiniteDuration(30, TimeUnit.SECONDS)
	private final def waitForCompletion[T](f: () => Future[T]) =
	PlatformCompat.waitAtMost(f, munitTimeout, munitExecutionContext)

The Scala Native implementation doesn't support timeouts (due to limitations of the single-threaded runtime). And actually I suspect the JavaScript one is broken too with the default parasitic execution context.

munit/munit/native/src/main/scala/munit/internal/PlatformCompat.scala

Lines 22 to 28 in 166698e

	def waitAtMost[T](
	startFuture: () => Future[T],
	duration: Duration,
	ec: ExecutionContext
	): Future[T] = {
	startFuture()
	}

However, it is possible to implement timeouts for Scala Native when also overriding the ExecutionContext with a more sophisticated runtime.

For example the QueueExecutorScheduler in Cats Effect Native supports timeouts. Since we are using the Cats Effect runtime in munit-cats-effect, I would like to be able to support test timeouts there by overriding waitForCompletion.

Of course we could solve this in userland by adding timeouts to the IO-transform in munit-cats-effect, but then it wouldn't work for non-IO-based tests that also happen to be running in a Cats Effect suite.

[armanbilge]

I decided to solve this in user-land. MUnit timeouts have other caveats, like lack of support for cancellation.

• Implement test timeouts typelevel/munit-cats-effect#233