Avoid Nesting when you're Testing

I feel like the utilities like changeUsernameInput and clickSubmit can be nice, but the tests are simple enough that duplicating that code instead could simplify our test code a bit.

I have a strong dislike for nesting like this. I've written and maintained thousands of tests that were written like this and I can tell you that as painful as it is for these three simple tests, it's way worse when you have thousands of lines of tests and wind up nesting even further.

Read at Kentcdodds