I have been learning MVC recently and have started creating my own framework (for learning purposes only, of course) from http://anantgarg.com/2009/03/13/write-your-own-php-mvc-framework-part-1/
I want to be able to extend these base classes but first I would like to be able to unit test them. Does anyone have an idea how I would go about testing the base Controller, Model and Template classes?
Thanks in advance!
Just write test classes, preferably mirroring your framework structure (eg ControllerTest, ModelTest, etc), that put the classes through their paces, meaning putting in some data and checking the output. If your code is well-structured, should be quite easy to implement.
Edit
Basically, what you test in a unit test is if ( Class::methodToTest( $input ) === $expected_output ). The output must always be identical for the same $input. If this is not the case, or you can't test write a test case like this, it's often an indicator that your code is not well structured (object oriented and loosely coupled).
Your Template::render() method for example, is not testable because it prints the data instead of returning it. Now, you could work around this by using ob_start(), but better anyway would be to chop the function into smaller parts, that return values instead of directly printing them.
It's a bit abstract, but I hope you get the point.