Lightweight Continuous Integration for PHP

This post describes a simple, lightweight strategy for implementing Continuous Integration on PHP-based software projects. This approach happens to use Subversion for version control, PHPUnit for unit testing, and Phing to automate the processes involved, but hopefully the principles are generally applicable.

The post won't strive to be exhaustive or encyclopaedic, rather it will present a simple proof-of-concept and a brief overview of the tools that are available to PHP developers. But first some background...

Unit Testing Code which Consumes SOAP Services

One of the trickiest aspects of unit testing or Test Driving an application's code is testing those parts of the system which depend on an external system, such as a database or a SOAP service.

In this post I'll outline an approach to testing a class which happens to communicate with a third-party SOAP service using PHP's built-in SoapClient class. Hopefully, the principles involved will be applicable to the more general case of testing code which relies on an external system.

Presentations on Slideshare

I've been doing a bit of presenting at work recently, which has meant getting my head around making up slides (using OpenOffice, of course). It all feels a little bit Dilbert, in a way.

Anyway, there's nothing particularly groundbreaking or PlayPhone-specific about these slides, so I've put them up on Slideshare in case anyone fancies a look.

PHPTuring

A few years ago, as an exercise in Test-Driven Development, I wrote a Turing machine simulator in PHP and imaginatively named it PHPTuring.

I had completely forgotten about it until today, when I dug it out for another look. Truth be told, I still haven't seen a Turing machine done any better in PHP, and apart from a few syntactical niceties (removing closing PHP tags as per the Zend way, neatening up the PHPDoc blocks) I'm actually pretty comfortable with the code.

Using it is a breeze. It reads pipe-separated tapes and newline plus pipe-separated instruction sets like so:

<?php

$prog = '0|1|1|R|0\n0||1|R|1\n1|1|1|R|1\n1|||L|2\n2|1|||stop';
$tape = '1|1|1|1|1|1||1|1|1|1|1|1|1|1';

$machine  = new Machine();
$compiler = new SimpleCompiler();
$parser   = new SimpleTapeParser();
$debugger = new SimpleDebugger();

$debugger->watch($machine);

header('Content-type: text/plain');
$machine->run($compiler->compile($prog),
              $parser->parse($tape));

It should work with other formats, so long as someone writes parsers for them. Similarly, the debugger is just an Observer that dumps the state and tape to the screen at each step, but it could easily do something more subtle some day.

The code ships with full tests, and is available for download on PHPTuring's Sourceforge download page.

So why am I banging on about it here? I don't know. Maybe just because I like it, because it was the first afternoon's coding that really got me test-infected, and because I'd be interested in any feedback.

JsUnit

Just a quick post to mention that, yes, my commitment to TDD show no signs of abating, especially in the face of the various unfamiliar technologies with which I've been working recently.

Today I came across JsUnit. Which may be old news to many, but I don't stray into JavaScript territory very often, and when I do, I'm usually quite frightened!

And how do developers reduce fear? Yup, we write some tests.

JsUnit has a nice UI, has maybe a 5 minute install/learning curve for anyone familiar with xUnits and just works. The only downsides I've found so far are that i) it doesn't work with my adored Opera and ii) some of the debugging messages are written in the sort of cryptic, broken English that suggests that the contributions of a native speaker might be welcome here.

Anyway, long story short, it's nice to know that even in the dark, dark world of client-side scripting, the gospel is spreading.