Createing a Test DB Object.

I need to test a bunch of code that extensively uses a mysql database (both selects and inserts), and I want to do it without actually writing to the database.. Instead of commenting out all of the $db->query($insert_query) statements and echoing $insert_query, I thought I'd make the following object: class TestDB { var $realDB; function TestDB(&$o) {

       echo $o;
       $this->realDB = &$o;
       echo $this->realDB;

} function query($q) {

       echo $q;

} function getOne($q) {

       return $this->realDB->getOne($q);

} function getRow($q) {

       return $this->realDB->getRow($q);

} function &resetDB() {

       return $this->realDB;

} } Then, in my code, I instantiate it like so:

           $tmp = new TestDB($db);
           $db = &$tmp;

But this doesn't work, and I can't figure out why. When I try to call $db->getRow($q) I was getting an error that said that I couldn't call a member function of a non-object. I've changed things around now, and I'm just not getting anything. Any idea why I would get the non-object error? Thanks.