On the Hackernoon site today Sebastian De Deyne has written up a tutorial showing you how to use Watchman to automatically run PHPUnit tests for your application when things change. Watchman is a tool from Facebook that watches files and directories for updates and execute actions based on the changes.

Watchman watches files and triggers actions when they change. The reasoning behing choosing Watchman: it’s easy to install, simple to configure, and reliable.

The watchman-make command - which ships with Watchman - is a specialised interface for Watchman to invoke build tools in response to file changes - exactly what we need!

In the setup he creates, Watchman is used to look for changes on files in either the project's src/ or tests/ directories and execute a bash script (code provided) that runs the tests and outputs the results. He walks through each line of the script and Watchman command, explaining how it works and what the option points to. You can see the results here of an edit to a test and the output in a Terminal window once it's saved.