Are we still using Open Radar? Been a while since I’ve filed a bug report with Apple, but this one was too bad to let go.
Xcode 9.4.1 will not run unit tests for Cocoa Touch frameworks on macOS Mojave.
If you haven’t upgraded to Mojave yet and you’re working on any Cocoa Touch frameworks projects, you might want to hold off until this is fixed. The workaround is to run your unit tests from the command line, but that’s no fun at all.