In #271, @paweldudek fixed a problem where registering a test observer too early causes the XCTest internal setup to perform incorrectly. This solution works, but has introduced a problem when updating Quick's Nimble version. It seems like the slight delay introduced using dispatch_async causes the Quick test for the number of ObjC tests performed to fail.

Kif had a similar issue, check out the Quick PR for more discussion on background + possible solutions. @phatblat has a theory.