A unit test in Java gives the developer the opportunity to test an object. For example, you might want to verify that a Person object contains the expected person name or perhaps the correct email address. In addition, you may want to verify that a property is not null.
The most common way to write unit tests in Java is to use JUnit, a free, open source unit-testing Java application. To learn how to write a unit test in Java, follow these seven steps.
junit-4.8.2.jarto your computer.
@BeforeClassannotation marks a method that will be called by JUnit one time before the tests are performed. The
@AfterClassannotation marks a method that will be called once after the tests have been run. The
@Testannotations mark the tests that will be executed by JUnit. Two tests are included in the program. The first test will verify that the first name has been successfully set to "Stephen". This test will succeed at runtime. The second test will assert that the last name is not null. This test will fail at runtime because although the Person object has been instantiated, the last name has not been set.
junit-4.8.2.jarto the directory that contains your Java program.
AssertionErrorexception. The name of the failing method and the program name are displayed in the output.