Java™ Application Development on Linux - Dator

312Chapter 13JUnit: Automating Unit Testing13.7REVIEWWe have shown you how to download JUnit and get it running. We have discussedcreating a test case and creating a suite of tests. We’ve looked at theSwing GUI for JUnit but also at the command-line interface. We have shownhow our design translates to a minimal code implementation from which wecan begin testing. We’ve discussed the “design, test, then code” approach, andhow you can use it to track the progress of your implementation.13.8WHAT YOU STILL DON’T KNOWJUnit can be invoked from ant. It is an optional task (not part of the standardant release), but easy to install and get running. Both the junit.jar and ant’soptional tasks JAR file need to be in your classpath. That’s all it takes. Seehttp://ant.apache.org/manual/OptionalTasks/junit.html for moredetails.JUnit integrates well with Eclipse and other IDEs. It is easy to install andvery easy to use when it’s part of your IDE. For whichever IDE you choose,get the JUnit plug-in for it and use it.One area we haven’t yet discussed is how to do unit testing for the GUIportion of your application. The basic idea is the same. In order to manipulateyour GUI from the test, you may want to investigate the java.awt.Robotclass. It can be used to generate system input events such as mouse andkeyboard actions.In fact, we’ve only begun to describe the various ways that JUnit can beused for all kinds of testing. Our focus has been on unit tests during code development,but JUnit can also be applied to integration and release testing. Withany large Java application, it is crucial to have a good set of regression tests thatcan be rerun after features or fixes are added, or after classes have beenrefactored. JUnit has proven to be very valuable in these situations.Finally, remember that JUnit is only a tool. The GIGO law 2 tells us notto expect great tests just because we know how to run a tool. Test design, likeany good design skill, is art as well as science. Learning the art of testing willpay dividends in better code built faster.2. Garbage In, Garbage Out.