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An Early Look at JUnit 4
An anonymous reader writes "Elliotte Harold, proclaimed 'obsessive code tester', took an early look at JUnit4 and shows how to best utilize the framework in your own projects. Many feel that this is one of the most important third-party Java libraries ever developed. It promises to simplify testing by exploiting Java 5's annotation feature to identify tests rather than relying on subclassing, reflection, and naming conventions."
Unit testing for web apps has a long way to go. Normally, writing junit tests is less then or equal to the amount of work in writing the actual code. Writing unit tests for web applications is vastly more complex and time consuming.
At any major development place, *everything* is unit tested. Code coverage (how many lines of code are actually covered by the tests) is huge and should usually be above 70%. Unit tests aren't to make sure that your code is working correctly right now, unit tests are so that in 5 years when you change one class out of 6000 interdependant classes you can just run "ant test" and it goes back, runs all your tests and makes sure they still pass as they did when you first wrote it 5 years prior. Without unit testing, modifying any major, complex piece of software would be hopeless. You can unit test anything, including apps that require databases. You simply "mock out" the database using JMock and it stands in place for it like a fake database almost. The development I do is heavily dependant on Oracle and Java and JUnit/JMock are critical to the project's success. It is a common practice in open source now too as was seen by the recent release of Gallery 2.0 which is largely unit tested.
Regards,
Steve