How to reinstall ProjectUITests after deleting?

I know this may sound stupid, but I accidentally deleted my UITests target from my project. The folder "FifteenUITests" is still there with the proper files, but I get two errors. How can I reinstall my UITests target onto my project? The exact errors I get are below.

Error: 'FirebaseAuthInterop/FIRAuthInterop.h' file not found

Error in Terminal: [!] Unable to find a target named FifteenUITests, did find Fifteen.

#ios #swift #xcode