Daily builds
By incorporating compilation and testing into your buildfiles, you can follow the practice of performing daily builds, advocated by the Extreme Programming folks and others. Regardless of the number of features that you currently have implemented, you always keep your system in a state in which it can be successfully built, so that if someone performs a checkout and runs Ant, the buildfile will perform all the compilations and run all the tests without failing.
This is a powerful technique. It means that you always have, as a baseline, a system that compiles and passes all its tests. At any time, you can always see what the true state of the development process is by examining the features that are actually implemented in the running system. One of the timesavers of this approach is that no one has to waste time coming up with a report explaining what is going on with the system; everybody can see for themselves by checking out a current build and running the program.
Running builds daily, or more often, also ensures that if someone (accidentally, we presume) checks in changes that cause tests to fail, you’ll know about it in short order, before those bugs have a chance to propagate further problems in the system. Ant even has a task that will send email, because many teams set up their buildfile as a cron[97] job to automatically run daily, or even several times a day, and send email if it fails. There is also an open-source tool that automatically performs builds and provides a Web page to show the project status; see https://cruisecontrol.sourceforge.net.
