Havoc Pennington wrote:
- develop list of major apps that must be tested, check basic functionality of each. e.g. browser, office, mail, IM, etc.
- input methods work in these apps
- printing works properly in all 10 languages from these major apps
...
- verify that all browser plugins work (including the proprietary ones available from third parties)
Mozilla's basic functionality test suite (smoketest) which includes plugins testing is at http://www.mozilla.org/quality/smoketests/index.html