Mockery is a simple yet flexible PHP mock object framework for use in unit testing with PHPUnit, PHPSpec or any other testing framework. Its core goal is to offer a test double framework with a succinct API capable of clearly defining all possible object operations and interactions using a human readable Domain Specific Language (DSL).
Highly opinionated mocking framework for PHP 5.3+
vfsStream is a stream wrapper for a virtual file system that may be helpful in unit tests to mock the real file system. It can be used with any unit test framework, like PHPUnit or SimpleTest.
:heavy_check_mark: PHP Test Framework for Freedom, Truth, and Justice
Some helper classes for writing functional tests in Symfony
A MySQL engine written in pure PHP
PHP Mocking Framework
Mock built-in PHP functions (e.g. time(), exec() or rand())