What is Test Driven Development (TDD) and Unit Testing?
Test Driven Development is one of the rules of eXtreme Programming (XP). Originally, XP programmers wrote tests for any part of their code that could break. However, this soon evolved in to the practice of writing the tests before writing the actual code. This may sound strange, but there is reason behind this madness; by knowing what can go wrong, you have a better idea of what your code needs to be able to handle. TDD has evolved in to a process by which code is generated, as opposed to a testing process. It does still effectively perform tests, but that is more of a by-product. The first thing you need is a Unit Testing framework. You can write your own, but that is not necessary. Most people use one of the existing frameworks such as FlexUnit or ASUnit. In TDD, functionality is added in very small chunks: You come up with a test, you write the test, you write the code to satisfy the test, possibly refactor it to make it more efficient, and then start with the next test. Each test m
