What you need for this book
For better understanding and deepening of the knowledge acquired, it's advisable to comprehend the examples within a local workspace on your computer. As JUnit is written in Java, the most important thing you need is Java Development Kit. The sample code requires at least Java 8, which can be downloaded from http://www.oracle.com/technetwork/java/index.html.
Although it's possible to compile and run the listings from the command line, the book assumes you're working with a Java IDE, such as Eclipse (http://www.eclipse.org/), IntelliJ IDEA (https://www.jetbrains.com/idea/) or NetBeans (https://netbeans.org/). The sample application was developed using Eclipse and so are the screenshots.
As mentioned in the preceding paragraph, the book's code sources are hosted at GitHub, so you can clone your local copy using Git (https://git-scm.com/). The chapter and sample app projects are based on Maven (https://maven.apache.org/) with respect to their structure and dependency management, which makes it easy to get the sample solutions up and running. This allows a thorough live inspection and debugging of passages that are not fully understood.
Due to this availability of comprehensive sources, the listings in the chapters are stripped down using static imports wherever appropriate or use ellipses to denote a class that has content unrelated to the topic. This helps you to keep the snippets small and focus on the important stuff.
Apart from that, in the course of the book, several Java libraries are introduced. They can all be declared as Maven dependencies and can be downloaded automatically from the publicly available Maven Central Repository (http://search.maven.org/). For some examples, you can refer to the pom.xml files of the sample application. An overview of the testing toolset is given in Chapter 1, Getting Started.