Update Promise Testability #70
Description
Currently, user auth is done in one big thunk using the fetch API. We need to figure out a way to stub out server requests, so that we can test the thunk thoroughly. Our assertion library expect has some things in it for spying on function calls. But these require us to pass in the fetch API as a callback. At the best, figure out a way to test the promises. At the worst, the login method will need to be refactored.