Testing utilities in Go.
I should probably be using something like Testify, but since I am just beginning with Go, I thought it was too early to chose and rely on a third-party library for my humble testing needs. Furthermore, writing this is also a learning exercise.
That said, credits where credits are due: I learned quite a bit looking at Testify's code, and its influence can be seen in my code. And I actually tried to make my assertions have signatures close to those in Testify, so that I can easily migrate if I ever feel like doing this.