Can't Run Tests

[NathanielScottStevens]

I can't figure out how to run the tests for this repo. I've tried ember test and npm test but neither work. When running ember test --server I get
Error: Assertion Failed: The tests file was not loaded. Make sure your tests index.html includes "assets/tests.js". at http://localhost:7357/assets/vendor.js, line 17726 ReferenceError: Can't find variable: QUnit at http://localhost:7357/assets/test-support.js, line 1756
I'm sure I must be missing something obvious.