We have a automated build process that generates nightly (sometimes sooner), both linux (tarball) & windows (installer) builds.
http://buildbot.wz2100.net/files/bugfixes/ (This is the main bug fixing branch that will be merge to both master & 3.1)
http://buildbot.wz2100.net/files/3.1/ (this is where the next beta comes from)
We also have master builds available here http://buildbot.wz2100.net/files/master/ that is much different from 3.1, and is testers are badly needed for this version!
When we fix things, it gets put into bugfixes, and then it is merged to both master & 3.1
When we have specific things that should NOT be in both master & 3.1, then we only update the required branch, and not bugfixes.
There is sometimes lots of activity, as can be shown here:
https://github.com/Warzone2100/warzone2 ... s/bugfixes
https://github.com/Warzone2100/warzone2100/commits/3.1
Currently, the only disadvantage of getting these builds is, that it won't work with the next newer build, and also, if you play multiplayer games, everyone needs to have the exact same build or you can't connect.
For example, a windows users gets http://buildbot.wz2100.net/files/bugfix ... de0c41.exe then the linux user must also get the same revision http://buildbot.wz2100.net/files/bugfix ... c41.tar.gz
[linux only section, for those that are not afraid to compile things]
Spoiler:
As far as testing goes, it is pretty difficult to know exactly what might have been broken again.
You can get a rough idea by looking at the activity of what is going on, and see if a certain thing that says was fixed, is actually fixed.
If it isn't fixed, then reopen the ticket again, and tell us!
If you find a new bug, then open a ticket http://developer.wz2100.net/newticket and tell us!
*thanks to NoQ for spotting a typo. (Will be pruning posts based on content, and how it relates to this subject.)