I ran some tests on Swift for Linux today, using the swift:5.8-amazonlinux2 Docker container.
I was surprised to find that the fulfillment(of:timeout:enforceOrder:) async method for asynchronously waiting on test expectations, and which resolves & works as expected on Mac & Xcode, seems to be missing from XCTest on Linux.
As far as I can tell, the rest of XCTest on Linux seems to be present & work as expected. (That method is documented here, and has been around since Xcode 11 so it's not a new feature by any means.)
So what am I missing? Is this method actually not included in Linux, or is there some other way to import it on Linux that I don't know about?
It seems to have not yet been added; here is an issue on the open-source version of XCTest noting the absence of fulfillment(of:timeout:enforceOrder:) async:
https://github.com/apple/swift-corelibs-xctest/issues/436