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

It seems there are several bugs in Xcode8 that can cause this. However I have found a solution for the case where Xcode tries to find the TEST_HOST app within the Intermediates/CodeCoverage/ folder. (I tried all other solutions with the module names etc and it didn't work for me.)

The issue itself seems to be that Xcode does not even try to build the app before running the tests. However once Xcode is able to find the TEST_HOST in the folder it will rebuild when launching the tests. That's how we can find our way around it.

Two possible solutions:

If you don't have to have code coverage: Go to your unit test target's Build Settings and set Enable Code Coverage Support to No and deactivate code coverage in your build scheme's test setting. (Edit scheme, select Test on the left). If you want to run your unit tests and still get that TEST_HOST error message, try building (CMD+B) or running your app. Then you can run your tests without that error. Voilá.

If you need code coverage: You can follow a certain workaround to get that Intermediates/CodeCoverage/.. folder filled. Once the app is inside Xcode will rebuild for the unit tests as it should, but you need to get it filled once. This is how you do it:

• In the app and the unit test target select No for "Enable Code Coverage Support"
• Then in the "General" tab of the unit test target set the test host application to "None"
• Uncheck "Allow testing Host API"
• Try to start unit tests. Xcode will now at least try to build. If Xcode gives a build error (sometimes Xcode complains about Cocoapods here in my experience), try building once again.
• Re-check "Allow testing Host API" again in the Unit Test target
• Try running the tests again as above. Xcode should complain.
• Now set the test host to the app.
• Now the tests should run through. (Until you run a clean, then you'll have to re-do these steps..)

I know, it's bothersome. But it's the only solution to the problem so far.