VG Tech Blog: Mocking the File System Using PHPUnit and vfsStream

On the VG Tech blog today there's another post related to unit testing (here's one from before) but this time they're talking about mocking the filesystem with vfsStream, a powerful tool that lets you interact with PHP streams as a virtual file system.

This article is about how to mock the file system when writing unit tests, and it will be rather code-heavy. [...] PHPUnit is the de-facto standard for unit testing in PHP projects, and this is what we will be using together with vfsStream in this article.

The include the code for a simple storage driver (VGF_Storage_Driver_Filesystem) to use with vfsStream with "store", "delete" and "get" methods. Also included are examples of using vfsStream to check things like directory existence, if a file exists, or if a file can be read. A few simple assertions are set up in their sample test to check the methods in their "VGF_Storage_Driver_Filesystem" class.