JUnit test classes are Java classes separate from the classes you want to test. Each test class can contain many test cases, which are just methods marked to be executed when JUnit tests are executed. A test suite is a collection of test classes.
The convention is to assign the test class the same name as that of the class you want to test, and append Test to that name. For example, if you wanted to test the Course class from the previous chapter, then you would create a JUnit test class and name it CourseTest. Test case (method) names start with test, followed by the name of the method in the class that you want to test; for example, if you wanted to test the validate method in the Course class, then you would create the testValidate method in the CourseTest class. Test classes are also created in the same package as the package in which the classes to be tested are present. In Maven projects, test classes are typically created under the src/test/java folder. The convention...