Testing untestable code

Testing software applications with the help of unit testing facilities is an widely-adopted standard in the software development industry today. Even the PHP community provides such tools to automate the testing of PHP applications. Unfortunately there exist legacy applications that are not testable by their internal design. Testing an single component of such an application in isolation is not possible in those cases due to their dependencies on other components. This often leads to the point of manual testing which is cost-intense and error prone.

In the first part of the session it is shown how the dynamic nature of PHP itself can be used to manipulate existing dependencies to be able to test a single component of the application on its own. In the second part of the session an additional layer of abstraction is introduced. By using that layer it is shown how to transform components of the original source code into testable code fragments.