Calling waitUntil in a QuickConfiguration times out for AsyncSpec about nimble

[younata]

Yeah. This is unsurprising, but still disappointing. It's also a bug with Quick, not Nimble - you'd get similar behavior if you tried the following code:

class AsyncConfiguration: QuickConfiguration {
    override class func configuration(_ configuration: QCKConfiguration) {
        configuration.beforeEach {
            let start = Date()
            RunLoop.main.run(until: Date(timeIntervalSinceNow: 2))
            expect(date.timeIntervalSince(start)).to(beCloseTo(2, within: 0.01)) // this assertion will fail when run with an async spec.
        }
    }
}

AsyncExample will run the stuff in your QuickConfiguration, as a matter of fact. This is desired because using any kind of waiting behavior in that kind of global configuration is an edge case (QuickConfiguration is meant more for doing stuff like configuring your test suite, not waiting for stuff to be available).

This is an issue when you try to run the sync versions of waitUntil, toEventually, etc. because those use APIs which no-op when run in an async context.

Possibly we might be able to get around this by detecting these cases and run them on the main actor using MainActor.run, similar to what we do for the suite hooks (i.e. the beforeSuite and afterSuite things) (see https://github.com/Quick/Quick/blob/main/Sources/Quick/Examples/AsyncExample.swift#L38-L40).