One Line Observers

I’ve started creating single line observers like this

<?php
class Mycompany_Mymodule_Model_Observer
{
    public function someMethod($observer)
    {
        Mage::helper('mycompany_mymodule/observer')
        ->someMethod($observer->getCustomer());
    }
}

The logic is punted to a helper class. This way the helper receives only the objects it needs (in the example above, customer), and can be tested/developed in isolation from the actual event.

So far it’s working a heck-of-a-lot-better than the selenium tests I used when writing checkout event observers.