Tests stop working under xcode 8 TEST_HOST error

Question

I want to start tests under Xcode 8 and it fail in the beginning. My error is:

Could not determine bundle identifier for MyProjectTest\'s TEST_HOST:

Answer 1

Quitting Xcode and removing DerivedData folder at fixed the problem for me.

$ sudo rm -Rf Library/Developer/Xcode/DerivedData

Shame on you, Apple!