xUnit is the collective name for several unit testing frameworks. PHPUnit is the most used framework for unit testing during software development in PHP. It is representative of family-based frameworks XUnit, based on SUnit package, created by Kent Beck.The main principle of PHPUnit is – as early you find errors in the code, as soon you can fix them. PHPUnit use the assertions to check the behavior of test code unit, as the other frameworks for unit testing .
Codeception – is PHP testing framework. It supports writing of unit, functional and acceptance tests in one way. Based on Symfony2 Components, PHPUnit, Codeception is a mature and stable project, well-tested and documented. It’s open-source and MIT licensed.