Unit testing of an API using JUnit

According to Wikipedia, more than 30% of the projects hosted on GitHub include JUnit—one of a family of unit testing frameworks collectively known as xUnit that originated with SUnit. It is linked as a JAR at compile time and resides (since JUnit 4) in the org.junit package.

In object-oriented programming, a unit can be an entire class but could be an individual method. We've found the last part—a unit as an individual method—the most useful in practice. It serves as the basis for the examples of the recipes of this chapter.

Getting ready

At the time of writing, the latest stable version of JUnit is 4.12, which can be used by adding the following Maven dependency...