Book Image

Mastering Software Testing with JUnit 5

By : Boni Garcia
Book Image

Mastering Software Testing with JUnit 5

By: Boni Garcia

Overview of this book

When building an application it is of utmost importance to have clean code, a productive environment and efficient systems in place. Having automated unit testing in place helps developers to achieve these goals. The JUnit testing framework is a popular choice among Java developers and has recently released a major version update with JUnit 5. This book shows you how to make use of the power of JUnit 5 to write better software. The book begins with an introduction to software quality and software testing. After that, you will see an in-depth analysis of all the features of Jupiter, the new programming and extension model provided by JUnit 5. You will learn how to integrate JUnit 5 with other frameworks such as Mockito, Spring, Selenium, Cucumber, and Docker. After the technical features of JUnit 5, the final part of this book will train you for the daily work of a software tester. You will learn best practices for writing meaningful tests. Finally, you will learn how software testing fits into the overall software development process, and sits alongside continuous integration, defect tracking, and test reporting.
Table of Contents (8 chapters)


As we know, the general structure of a test case is composed of four stages: setup, exercise, verify, and tear down. The actual test happens during the second and third stage, when the test logic interacts with the system under test, getting some kind of outcome from it. This outcome is compared with the expected result in the verify stage. In this stage, we find what we call assertions. In this section, we take a closer look at them.

An assertion (also known as a predicate) is a boolean statement typically used to reason about software correctness. From a technical point of view, an assertion is composed of three parts (see the image after the list):

  1. First, we find the expected value, which comes from what we call test oracles. A test oracle is a reliable source of expected outputs, for example, the system specification.
  2. Second, we find the real outcome, which comes...