Job Ready Java

Lesson 30Doing Unit Testing

We now have a complete application, which is pretty cool! But how do we know we're done? How do we know that we've met all the requirements of the project? And how do we know that there are no errors? Unit testing is a technique that can help us answer these questions.

In this lesson, we will introduce the concept of unit testing, look at the JUnit automated unit testing framework, see how we can test both stateless and stateful code, and do a code-along where we add unit tests to the Class Roster application.

LEARNING OBJECTIVES

By the end of this lesson, you will be able to:

• Explain what unit testing is
• Differentiate between black-box and glass-box (or white-box) testing
• Differentiate between stateful and stateless components
• Describe test-driven development
• Trace the process of Red/Green/Refactor
• Explain the usage of test stubs
• Use JUnit to create, run, and document unit tests
• Explain how the Given/When/Then approach to unit testing works
• Describe what makes a good unit test
• Trace the unit testing design and implementation process

UNIT TESTING

Software is tested at several different points during the development of a project. Unit testing involves testing the lowest-level components of an application and is done by the software development team. The developer responsible for developing a particular component is also generally responsible for creating the unit tests for that component.

Modern unit testing involves the use of automated ...