Testing
In Chapter 4, Best Practices for Design and Development, we had a look at Test-Driven Development (TDD), quickly touching on the concept of unit testing. Now is the right time to make some deeper considerations around the concept of testing and return to some topics that we have taken for granted so far.
Unit testing
Unit testing is the most basic technique for software quality assurance and, as we have seen, the tool behind TDD.
Unit testing aims to provide testing (usually automated) for the smallest unit of identifiable software. In the Java world, this means testing at a class and method level. The tests involve calling the method with a defined set of inputs and checking (with assertions) that the output complies with the expectation (including expected failures).
The reasoning behind it is that each method is tested individually, so the tests can be simple and pervasive. This also allows bugs to be identified early and in the exact spot where they are introduced...
