Why, Fatal error: Class 'PHPUnit_Framework_TestCase' not found in …?

The PHPUnit documentation says used to say to include/require PHPUnit/Framework.php, as follows:

require_once ('PHPUnit/Framework/TestCase.php');

UPDATE

As of PHPUnit 3.5, there is a built-in autoloader class that will handle this for you:

require_once 'PHPUnit/Autoload.php';

Thanks to Phoenix for pointing this out!

The answer was due to hidden characters located in the lessons.db file.

The error shown had nothing to do with this and I would like to thank everyone who took the time to give their two pence.

You access the property in the wrong way. With the $this->$my_value = .. syntax, you set the property with the name of the value in $my_value. What you want is $this->my_value = ..

$var = "my_value";
$this->$var = "test";

is the same as

$this->my_value = "test";

To fix a few things from your example, the code below is a better aproach

class my_class {

    public  $my_value = array();

    function __construct ($value) {
        $this->my_value[] = $value;
    }

    function set_value ($value) {
        if (!is_array($value)) {
            throw new Exception("Illegal argument");
        }

        $this->my_value = $value;
    }

    function add_value($value) {
        $this->my_value = $value;
    }
}

$a = new my_class ('a');
$a->my_value[] = 'b';
$a->add_value('c');
$a->set_value(array('d'));

This ensures, that my_value won't change it's type to string or something else when you call set_value. But you can still set the value of my_value direct, because it's public. The final step is, to make my_value private and only access my_value over getter/setter methods