Testing with string objects in PHP

As shown in the last post there are benefits to instantiating the class under test in setUp(). With objects its simple to create them and maintain reference to them so you can change them, but what about things like strings? Unlike in many other modern languages, strings are not objects in PHP. They are not passed by reference. The good news is while strings are not objects, objects can be stings.

class String {
    public function set($str) {
        $this->_str = $str;
    public function __toString() {
        return $this->_str;

This class can be used as a string. It can work in PHP's string functions and any other place a string is desired. So pass this to the class you're testing and then change it later. It works all the same.

Its important to note that if you are using these in your test setUp() that you can't do work using that string object during the construction process of the class under test. Initially this slipped my mind as its part of my standard practices. I believe you should never do any work in your constructor at all.