Eric Hogue on April 9th, 2012

Continuous testing is a way to automate the execution of your tests while you work. This makes the feedback loop very short. As soon as you save a file, the tests are run and you know right away if anything fails.


I discovered continuous testing over a year ago when I watched a video where Corey Haines performed a kata in front of a crowd. He was doing it in Ruby and using Autotest to run his test suite. I tough it was awesome that he immediately saw the result of his changes without having to do anything.

Back then I had used PHPsrc. It’s a great tool, but I didn’t like that I had to take my hand off the keyboard and click on a button to run my tests. So I was mainly running them from the command line.


When I saw Autotest, I was immediately sold and I looked for something similar in PHP. Sadly I didn’t found anything like it. So after a while I wrote something for myself. I called it AutoPHPUnit. It uses libnotify to watch the file system. Every time a file is changed, it runs PHPUnit. You can also specify a configuration file for PHPUnit.

It worked well for me, I really loved using it. But it was not very flexible.


Then I read the book Continuous Testing: with Ruby, Rails, and JavaScript (affiliate link) that I won at the Code Retreat in Quebec city.

In the book, the authors use watchr to monitor the file system and perform any actions when a file changes. Watchr can be used to monitor any kind of file, so it’s more flexible than my solution. And you tell it what to do with a Ruby block so it can react to changes any way you want.

To install it, you need to have Ruby already installed on your machine. Then you use RubyGems to install it. Simply run “gem install watchr” and you will have watchr on your machine. If you are not using RVM to manage your versions of Ruby, you might need to use sudo to install watchr.

You can then create a simple Ruby script. Calling the function watch() with a regexp for the files you want to watch and the block you want to execute when a file changes. Then, you run watchr passing it the script file as a parameter.

Here’s a simple script to run PHPUnit:

watch ('.*\.php$') {|phpFile| system("phpunit -c phpunit.xml")}

I watch every file that ends with ‘.php’. When watchr detects a change, it simply runs PHPUnit for me.

watchr running

watchr running


Using watchr like this is great if you have enough screen space to show a terminal beside your code. But if you can’t have a terminal on the screen at the same time as your editor, you can use notify-send on Ubuntu to get a pop up in the notification section.

watch ('.*\.php$') {|phpFile| run_php_unit(phpFile)} 

def run_php_unit(modified_file)
    if (system("phpunit -c phpunit.xml")) 
        system("notify-send 'All test passed'")
        system("notify-send 'Test failed'")

You can add any logic you want. In the Continuous Testing book they go further. You can have it display notifications only when the tests fails and when they pass again for the first time. They also count the numbers of successful runs and display notifications every 5 consecutive successful run.

watchr notification

watchr notification

Beyond PHP

The main advantage of watchr is that it is not limited to only testing Ruby or PHP. Since you are using a block of Ruby code, you can do almost anything. At work, we are starting a little Node.js project, and I plan on using it to run the Vows tests.

Here’s a few other things you can do with it

  • Compile CoffeeScript
  • Run PHP Code Sniffer
  • Run lint tests
  • Minify your JavaScript and CSS

Basically, anything you can automate can be ran every time a file of a certain type is changed. I’ve seen only one drawback to watchr, it does not see new files. So when you add files, you need to restart it if you want them to be monitored.

Update 2012-09-04

I posted a follow up about Continuous Testing. I now use Guard to run my tests automatically.

Tags: , , ,

  • Guille


    @ajessu on Twitter has just told me about this article… I just wanted to tell you that some time ago we had a tool published in GitHub that provides test automation for phpunit, phpspec and behat. You can check it out at


    • Eric Hogue

      Hi Guille,

      Your tool looks pretty good. I will give it a try.


  • Basit @ PHP Tutorials

    Very nice tutorial, It helps me alot. Thanks for writing for us :)

  • Pingback: Continuous Testing in PHP with Guard | Eric Hogue's Blog()