Quality Assurance in PHP Projects

This is an abstract for a chapter from a book on Quality Assurance in PHP Projects.

The eZ Components project was started with the goal to create a high-quality set of independent building blocks for PHP 5 based application development. Making extensive use of unit tests and sticking to strict development and documentation standards were defined as the basic methodology. One of the biggest challenges in terms of testing and quality assurance so far was the eZ Webdav component.

The eZ Webdav component is intended to provide a modular WebDAV server to be embedded in any kind of web application. Its architecture is built to be as customizable and extensible as possible, while it tries on the other hand to compensate the weaknesses of the RFC and common WebDAV clients.

Testing a server is a challenge in general. Testing the WebDAV component brought us to the limit of unit testing and forced us to find new ways of using PHPUnit to ensure code quality and to obviate regressions. Unavoidable deep code dependencies in some parts of the server enforced the extensive use of mock objects to stick to the unit test paradigm. In some areas, like avoiding regressions in the adjusted behavior against special clients, unit testing was even impossible. For this reason, special record/playback-based tests were created and implemented using PHPUnit.

Tobias Schlitt is an active member of the PHP community and works for eZ Systems on the eZ Components.