[TEST] payments mock flow

@geertweening @wltsmrz 

will be cleaning up log output
Setup and teardown should be external to the test file as you'll be repeating this a lot (assuming you're going to write more tests in this format). If you're only writing these payment and server tests, forget it, I guess.

I'm kind of opposed to having all of the logic in the test fixtures and sharing a global EventEmitter rather than in each test case. From what I can tell, the contents of this `describe()` compose one test. Keep in mind that you'll have to write tests for invalid input eventually.