Im testing 1 product... and cleaning up a few things before it can go live... and another product is about 70% done.

I do have a 3rd project just starting, so I think from reading a post above I shold write tests before the code.... What i've always done is just document before hand, something like

PHP Code:
class document {
     * Add a document to the database, blah blah
     * @param array $data Data to be added to the database
     * @return bool
function addDocument$data ) { }

So, really, I should do something like that and then write a test class for it, correct?