Using AssertJ for assertions

In this recipe, we will add AssertJ to your classpath (or check if it's already there) and take a look at a test that should show the concept that lies behind the AssertJ library.

Getting ready

First, let's check the differences between the different AssertJ JAR files:

• assertj-core: This file contains the vast majority of assertions (there is rarely a need to have any additional dependencies)

• assertj-guava: This file contains additional assertions for some of the Guava library related classes

• assertj-neo4j: This file contains additional assertions for the Neo4j graph database related classes

• assertj-joda-time: This file contains additional assertions for the JodaTime library related classes

• assertj-assertions-generator-maven-plugin: This is a Maven plugin for generating AssertJ assertions

In most cases, all you need is assertj-core since it already has plenty of useful assertions.

Regardless of the fact that you are using JUnit or TestNG, you still have to add assertj...