"Message from debugger: unable to attach" when running Tests on OSX app

Question

I am unable to run my tests on my OSX app - the project builds fine but when I run Product -> Test in Xcode 8.2. It says : Message from debugger: unable to attach

How do I get my tests working again?

Answer 1

What solved the problem for me was to enable signing on the test target. You need to go to your project's settings, go to your target and in general, under Testing, you have the Signing section. Click on the big button "Enable signing" (or something like this). You may have to deal with provisioning profiles but it wasn't the case for me.