I make checklist, but i don't confident this list is right,
Drupal QA
Cheсklist
Functional
Security
Load & Performance
Localization
Usability
1.Functional
check functional on server phpmail, and other functions and apps for server
check watchdog
check version module drupal.org on site.
test developer modules (write test by simple test).
Automated Functional Testing Selenium , Windmill etc
2.Security
check configure on server (rewrite for module, files private etc), security file permission
check security review, (drupal module)
delete files in “/”
disabled not required functions (xmlrpc, etc)
check permission (anonymous, editor, user)
check input format(filtered, full)
captcha/recaptcha
tested all functional for manage user, recovery password, register etc.
review reports http://drupalsecurityreport.org/
3.Load & Performance
Review web server configuration
Review database configuration
Review PHP configuration
xhprof, jmeter test performance load
Server cache
Drupal optimization
check by online services
4.Localization
check translating UI,
5.Usability
check JS code on site
error message, message register etc
check link(link checker broken links)