Re: any thoughts on self-testing classes?

Very good answer, thank you. Sorry, but what is PPP? On Sat, Mar 28, 2009 at 11:42 AM, Greg Beaver <greg@chiaraquartet.net>wrote: > Dmitri Snytkine wrote: > > Just wondering what experienced developers think about self-testing > classes, > > - classes that include their own test() method inside the class which > runs > > test suite and tests all methods. > > > > This is one way to have access to private methods while running tests. > > > > Any of you using this approach in your development? > > Hi Dmitri, > > I would not consider this approach simply because it mixes purposes, and > introduces all kinds of weird ways to screw up the intended normal > operation of the class. > > I would also suggest that this is not the way to solve the problem of > accessing private methods. > > After having used PPP for a couple of years in PHP now, I can report > that the best solution is to avoid the word "private" unless you really > mean "final" - as in the entire operation of the class would be > jeopardized if any change is ever made to the operation of a method. In > this case, slapping "private" in front of it is a very good idea. > > For most situations, once you switch "private" to "protected" you get > the best of both worlds. It becomes impossible to call a method from > outside the class hierarchy, but you can still extend the class and > override the method, which allows testing to work simply via a mock. > For instance: > > class MyMock extends Fancy_Class > { > public function whatever() > { > return parent::whatever(); > } > } > > This way, your test can simply instantiate MyMock and call whatever() > directly to test it. > > There are other problems with including test() methods inside the class, > one of which is that the memory usage of your class and load time > increases even with an opcode cache, all with deadweight code that is > never executed in normal operation. > > This is all another way of saying that if you design your code to be > testable, then you won't need to do anything awkward in the code itself > in order to test it. > > Greg >