For your open source projects you want to make sure that pull requests you merge don’t destabilise the project. Having a large number of unit tests in combination with a Continuos Integration platform like Travis-CI helps greatly. With this setup each pull request or new branch sent to your repo triggers a build and Travis-CI will let you know if all tests pass or not.
If you annotate your headers with appledoc then you can build nice class documentation viewable that integrates with the Xcode documentation viewer or can be put on a web server as HTML.
Now what about pull requests which add new functionality but which are lacking some documentation annotations? This blog post looks into using Travis-CI for making sure documentation is also complete on pull requests.