Error after renaming Xcode 6 project: “linker command failed with exit code 1 (use -v to see invocation)”

I saw the same error after changing the name, and I was able to fix it by clearing the “Test Host” values in the Build Settings of my “Tests” target:

Alternatively, If you need your tests to be able to run after changing the name of your project, you should be able to update the MyProject.app/MyProject value in both fields to reflect the new name of your project (ie. MyNewProject.app/MyNewProject)