Bitcoin integration/staging tree
Developers work in their own trees, then submit pull requests when they think their feature or bug fix is ready.
If it is a simple/trivial/non-controversial change, then one of the bitcoin development team members simply pulls it.
If it is a more complicated or potentially controversial change, then the patch submitter will be asked to start a discussion (if they haven't already) on the mailing list: http://sourceforge.net/mailarchive/forum.php?forum_name=bitcoin-development
The patch will be accepted if there is broad consensus that it is a good thing. Developers should expect to rework and resubmit patches if they don't match the project's coding conventions (see coding.txt) or are controversial.
The master branch is regularly built and tested, but is not guaranteed to be completely stable. Tags are regularly created to indicate new official, stable release versions of Bitcoin.
Testing and code review is the bottleneck for development; we get more pull requests than we can review and test. Please be patient and help out, and remember this is a security-critical project where any mistake might cost people lots of money.
Developers are strongly encouraged to write unit tests for new code, and to submit new unit tests for old code.
Unit tests for the core code are in src/test/ To compile and run them: cd src; make -f makefile.linux test
Unit tests for the GUI code are in src/qt/test/ To compile and run them: qmake BITCOIN_QT_TEST=1 -o Makefile.test bitcoin-qt.pro make -f Makefile.test ./Bitcoin-Qt
Every pull request is built for both Windows and Linux on a dedicated server, and unit and sanity tests are automatically run. The binaries produced may be used for manual QA testing (a link to them will appear in a comment on the pull request from 'BitcoinPullTester'). See https://github.com/TheBlueMatt/test-scripts for the build/test scripts.
Manual Quality Assurance (QA) Testing
Large changes should have a test plan, and should be tested by somebody other than the developer who wrote the code.
See https://github.com/bitcoin/QA/ for how to create a test plan.