Testing optical drives
A simple test, done by booting up an install disc and running the disc test (normally done by accessing the special options menu with the F6 button).
The big issue with testing an optical drive is making sure the disc used for testing is in good condition. The procedure for making sure a disc is good is much the same as testing a drive.
However, it is possible to test optical discs in greater depth than this, one can check whether all the data is perfectly intact on the disc, with no errors whatsoever, rather than just testing whether it is intact enough that it can be adequately retrieved by all means at the system's disposal, ie. including through the use of error checking and correction data.
Pressed discs behave somewhat differently than user recorded discs. However, the biggest problem with how our discs behave is how horribly scratched up they tend to get. It is helpful to filter out the badly damaged discs that pile up.