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.
Please note: Starting with version 1.0.0 the namespace of classes in vfsStream is org\bovigo\vfs. For the sake of simplicity this namespace part is omitted in any of the following documentation pages throughout the text. Versions before 1.0.0 don't have a namespace.