Get up to 40 % extra points for free! More info
Save up to 80 % on our Swift e-learning courses. Only this week!

Lesson 4 - Java Testing - Unit Tests of Real Applications I

In the previous lesson, Java Testing - Hamcrest, JUnit TestRule and Best Practices, we introduced the Hamcrest library, the rules annotation, and finally we mentioned the best practices for testing in Java. To make sure we don't end with just our calculator's tests, we'll show unit test codes from real applications in the following few lessons. These will be tests of a message analyzer, persistence layer (data storage), and tests of a random token generator. They will help you get a better idea of how such things are tested in practice.

Note: The examples will get more and more complex. Don't worry if you don't understand something in their implementation. You should mainly understand how the tests work, which test verifies which features and how it does it.

Tag analyzer test

The following test verifies that the TagAnalyzer class works correctly. It analyzes a message and searches for hashtags, as you know them from Facebook ("I've overslept again. #mondays").

Let's take a look at the basic structure of the test class with initialization and describe it below.


...End of the preview...

Premium article

Premium article is a large database made up of manuals and tutorials, whose main goal is to provide high-quality IT education to everyone. We started out in the Czech republic, where we display roughly a million articles per month and receive plenty of gratitude from our users. Thanks to our successful establishment, we are now bringing these articles to the rest of the world.

Although we are trying to keep our content free of charge, maintaining the site is a huge effort for everyone involved. Therefore, some content (exercises and more advanced material) costs network points. Don't worry, they're really cheap :)

Article description

Requested article covers this content:

In this tutorial, we'll analyze the source code of a unit test from a real Java application, where a class representing a message is tested for hashtags.

Limited offer: Learn all knowledge and save money

Buy articles and tests separately one by one 240 points
Buy all currently available articles in the section including all features for an exclusive price 204 points
Currently, you have 0 points
By buying this exclusive package, you'll have access to all 12 articles in this course including exercise submitting while saving $3.24. This offer is limited for the first articles only with an additional exclusive 15% discount.
You gain 204 points for adding an article to the site, or for $21.60 $18.36

Warning, by buying just this article you'll lose the limited 15% discount for the package of all the articles.

To access the article, you need 24 points
Currently, you have 0 points
You gain 24 points for adding an article to the site, or for $2.16

Before buying this article, you have to buy the previous one

Buying this article gives you unlimited access to it forever. You will learn some more and help us keep giving our site maintenance which helps you and others get better futures. It's a win-win.

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

You gain points 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.

You can get points immediately using:

Credit card SMS Wire transfer
Credit card SMS Wire transfer
Article has been written for you by David Capka
The author is a programmer, who likes web technologies and being the lead/chief article writer at 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 The author learned IT at the Unicorn University - a prestigious college providing education on IT and economics.
Activities (3)