Features

Using JUnit 5 in IntelliJ IDEA

One of the new features in IntelliJ IDEA 2016.2 is support for the new JUnit 5 testing framework.  Almost all Java developers will have used JUnit at some point, so it’s pretty exciting to find the newest version has evolved with the times and provides a number of new features, some of which may be familiar to those who have used other frameworks.

IntelliJ IDEA supports the ability to actually run tests written for JUnit 5 – there’s no need to use the additional libraries (like the Gradle or Maven plugins for example), all you need is to include the JUnit 5 dependency. Here we’re using Gradle to include the dependency to the M2 version:

Setting up dependencies

Once you’ve done this, you can start writing tests that use the new annotations:

Simple JUnit 5 test

Running these tests will give you familiar-looking results in the IntelliJ IDEA run window:

JUnit 5 test results

You’ll notice JUnit Jupiter is the test engine for the new JUnit tests, and that you can run both new and old tests.

At first glance, the new JUnit 5 tests are no different to JUnit 4 ones, other than the annotations being imported from a different package, and showing two types of runner on the results.

But JUnit 5 comes with some new features, such as the ability to add a readable name or description for the test, so you no longer have to rely on a method name, using @DisplayName:

Using @DisplayName

You can group assertions so that all assertions are run, regardless of whether one (or more) fails, giving you better visibility over the true state of a failure:

Grouping assertions

And you can use the @Nested annotation, so you can write BDD-style tests or group the tests in a class by some dimension:

Running @Nested tests

JUnit 5 also has a new way of handling expected Exceptions, by letting you assert specific Exceptions are thrown

JUnit 5 can expect exceptions

And you can even get the thrown Exception to check for further details:

Inspect Exception

These are just some of the features available to use in JUnit 5, and IntelliJ’s support for the new framework is also evolving.

If you think JUnit 5 looks interesting, download IntelliJ IDEA 2016.2 and take a look at:

And, of course, you can check out more of the features available in IntelliJ IDEA 2016.2.

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