Example of a Simple Test Case
Ava is a unique testing framework in that it is one of the few testing frameworks out there that recognizes observable resolution. It also makes asynchronous testing the default option when you write tests ensuring better performance. Another nice feature of Ava is that it has a nicer assertion output display.
Testdouble is an assertion library which specializes in create 'doubles'. Testdouble is different from Sinon because Testdouble will replace the function outright for which it is substituting when mocking out a function or object. It also makes it easier to track using a 'sandbox' API to alleviate the user from having to restore an original replaced function.