This project fulfils 7 user stories outlined by FreeCodeCamp and was built using TDD principles.
I implemented this solution using Create React App.
You can run the tests directly from the browser. To do so, first click the accordion on the top left hand side of the page, select 'Drum Machine' from the drop down menu and then click the 'Run Tests' button. To view the tests click the button below 'Run tests' which should be green having passed all tests and should have the text 'Tests 8/8'. If this is not the case, please refresh the page and run the tests again.