Using Hamcrest matchers for assertions

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

Getting ready

First, let's check the differences between the various Hamcrest JAR files:

• hamcrest-core.jar: This file contains the core functionality and a set of common matchers

• hamcrest-library.jar: This file contains a set of additional Hamcrest matchers

• hamcrest-generator.jar: This file generates code that combines many matcher implementations into a single class with static methods

• hamcrest-integration.jar: This file contains the integration of Hamcrest and other testing toolsrary.jar files

• hamcrest-all.jar: This file contains one JAR file containing all other JAR files

Most likely, you will use either hamcrest-core or hamcrest-all, depending on your needs.

If you are using JUnit 4 (from at least 4.9), you have the core version of Hamcrest already bound to JUnit. If you are using a...