Xcode 7 - Code coverage data generation failed

Question

When I run my tests I get an error:

Code coverage data generation failed.
Unable to retrieve the profile data files from \'UIDevice\'.

Answer 1

I was having this problem on Xcode 8.3 on Sierra 10.12.4

I opened the Keychain Access application on my Mac

After a few seconds, I got several system pop-ups asking for my password, to grant permissions to Keychain items.

I entered my password into the pop-ups, and then my tests starting working.