Which programming platform to use for the server-side application? Whilst I have to admit that I’m not the greatest fan of PHP, it’s definitely the best option. Why? Because I need to run this application locally on a minimal server and PHP is available wherever you find Apache, and the skills should have some commercial value.

I’ve recently read a great deal about agile development, TDD and employing software design patterns. As part of this project I’d like to apply some of what I’ve learned.

A test framework.

Now I’m going to need a testing framework, and I’ve gone for SimpleTest. This framework not only provides unit testing, but the ability to create tests for web pages. I prefer to run my test suites from the command line, which is relatively easy to arrange with the TextReporter object. I’ve combined the whole thing with Apache Ant to automate most of the tasks in the project, including deployment.

Unfortunately, it appears that SimpleTest doesn’t play particularly well with PHP5, although they’re in the process of making the transition.

I’ve encountered the mass of error messages generated as the result of E_STRICT. This is easily solved by using a customised php.ini file as an option at the command prompt when executing the test code. Once this is done you can see the actual test messages!

A more significant problem is that the Mock object code cannot be called as static class methods in the way the documentation suggests. A little snooping through the code leads me to think that it’s due to PHP4 without the static keyword in the method headers required by PHP5. I don’t have a work-round for this, and I don’t want to have to alter all this code. I hope they address this as the transition to PHP5 continues, but at the moment my code is simple enough for me to write my own mocks.

When all is said and done, if you know how to use any of the xUnit test frameworks, SimpleTest is very easy to set-up and use.

Driving with tests.

Simple the tests may be, but using them to steer the direction of your coding effort takes a different mindset. The hardest part is learning which questions to ask when developing your tests. Asking the right questions about functionality will result in clean, precise code.

There’s always a temptation add just a little more functionality, but resist it. The point is to remain in control of the code at all times. When it’s not working, it must be because you’ve added new tests describing new functionality. The code should never contain functionality that hasn’t been demanded by a test. Good refactoring can produce beautiful code without breaking the tests — still in control.

I think I’m getting the hang of it in relatively simple cases, but there’s much more to learn. I’ve found it a very liberating way to develop software, whilst remaining in total control — you are using version control?

Patterns in the code

Whilst there are loads of MVC based frameworks out there, I want to know how it works first hand. This topic is worth an article of it’s own, and that’s what I’ll give it.

There’s a good chance that the core application model will need to implement a facade pattern, but lets not make any assumptions.