Behind the Scenes of Redefining a Function

In the last episode, we talked about the philosophy of unit testing, i.e. testing in isolation without the function’s dependencies. In order to test in isolation, we need to know what each dependent function will do within the context of that test (i.e. given conditions) and then write a function that redefines the original in order to force it to do what it should. In this episode, you and I will dive into what is happening between the scenes in the PHP internals of user-defined names and memory. I’ll give you an overview to help you visualize how Brain Monkey through Patchwork allows you to dynamically (on-the-fly) redefine a previously declared function.