On the QaFoo.com site Manuel Pichler has posted a new tutorial about using unit testing, specifically with PHPUnit (really ending up on phpt) to test and be sure that your file upload handling is working correctly.
A question I am asked on a regular basis is, how you can test a file upload with PHP. In this blog post, I take a precise look at this topic and show you how to test your file uploads from within your standard testing environment, using widely unknown testing framework for PHP.
He shows how to use a custom $_FILES superglobal to mimic the upload process noting, however, that this won't work due to possible file handling on the backend. His alternative is to use a phpt test to push a raw posted file to the application and then check the results. He then shows how to take these functioning tests and drop them back into PHPUnit via it's "PhpTestCase" handling. You can find full code examples here.