Working with a legacy code base can be tricky. Developers who need to add new features or fix bugs often feel the need to tread lightly when working with older code, fearing that one wrong move might cause them to break something important. The same apprehension can affect developers who want to test legacy PHP applications. In this course, instructor Chris Hartjes guides PHP developers through the challenges of testing legacy applications, and steps through how to write tests for legacy PHP code bases.