Ever needed to try some testing in your own isolated environment? Wanted to test out your module or other piece of Magento without interfering with the system? Its easy. Create a file in your Magento app root and place the following lines at the top.
umask ( 0 );
Mage::setIsDeveloperMode ( true );
ini_set ( 'display_errors', 1 );
Save your file, and run it from your browser or command line. You’re all set!