Get up to 80 % extra points for free! More info:

Lesson 3 - Java Testing - Hamcrest, JUnit TestRule and Best Practices

In the previous lesson, Java Testing - The first unit test in JUnit, we introduced the very basics of JUnit and wrote our first unit test. In today's lesson, we're going to complete unit tests by introducing the Hamcrest library, which is newly supported by JUnit, and fundamentally changes the way we write assertions. We'll also discuss rules (TestRules) and at the end we'll mention best practices for writing unit tests.

Hamcrest matchers

Since JUnit 4.4, there's the assertThat() method available, bringing a new way to do asserts using Matchers from the Hamcrest library. By combining these matchers, we can create a complex expression easily. You may not be surprised that matchers are classes (again) with static methods, we can chain them and we're also able to write custom matchers. Using this new method results in great readability.

Let's see what one simple assertion would look like in the original syntax:

assertEquals(2, calculator.add(1, 1));

and now in Hamcrest:


 

...End of the preview...
Continue further

You will gain knowledge worth hundreds of thousands for a few crowns

You've come here and that's great! We believe that the first lessons showed you something new and useful
Do you want to continue the course? Go to the premium section.

Buy this course

Buy all currently available lessons with exercise submitting and other features for just $21.60
Current account balance $0
By buying this package, you'll have access to all 12 articles (12 lessons) in this course.

This article is licensed: Premium III, by buying this article, you agree with the terms of use.

What will you get from us in the next lessons?
  • Unlimited and permanent access to individual lessons.
  • High quality IT knowledge.
  • Skills to help you get your dream and well-paid job.

Article description

Requested article covers this content:

In this tutorial, we'll rewrite the previous unit test to the more modern syntax of the Hamcrest library, introduce TestRule API and best practices.

You gain credits by supporting our network. This is done by sending a helpful amount of money to support the site, or by creating content for the network.

Article has been written for you by David Capka Hartinger
Avatar
The author is a programmer, who likes web technologies and being the lead/chief article writer at ICT.social. He shares his knowledge with the community and is always looking to improve. He believes that anyone can do what they set their mind to.
Unicorn university David learned IT at the Unicorn University - a prestigious college providing education on IT and economics.
Activities