Grouping JUnit tests

Question

Is there any way to group tests in JUnit, so that I can run only some groups?

Or is it possible to annotate some tests and then globally disable them?

I'm using JUnit 4, I can't use TestNG.

edit: @RunWith and @SuiteClasses works great. But is it possible to annotate like this only some tests in test class? Or do I have to annotate whole test class?

Answer 1

You can create test Suite objects that contain groups of tests. Alternatively, your IDE (like Eclipse) may have support for running all the tests contained in a given package.

Answer 2

Do you want to group tests inside a test class or do you want to group test classes? I am going to assume the latter.

It depends on how you are running your tests. If you run them by Maven, it is possible to specify exactly what tests you want to include. See the Maven surefire documentation for this.

More generally, though, what I do is that I have a tree of test suites. A test suite in JUnit 4 looks something like:

 @RunWith(Suite.class)
 @SuiteClasses(SomeUnitTest1.class, SomeUnitTest2.class)
 public class UnitTestsSuite {
 }

So, maybe I have a FunctionTestsSuite and a UnitTestsSuite, and then an AllTestsSuite which includes the other two. If you run them in Eclipse you get a very nice hierarchical view.

The problem with this approach is that it's kind of tedious if you want to slice tests in more than one different way. But it's still possible (you can for example have one set of suites that slice based on module, then another slicing on the type of test).

Answer 3

To handle the globally disabling them, JUnit (4.5+) has two ways One is to use the new method assumeThat. If you put that in the @BeforeClass (or the @Before) of a test class, and if the condition fails, it will ignore the test. In the condition you can put a system property or something else that can be globally set on or off.

The other alternative is to create a custom runner which understands the global property and delegates to the appropriate runner. This approach is a lot more brittle (since the JUnit4 internal runners are unstable and can be changed from release to release), but it has the advantage of being able to be inherited down a class hierarchy and be overridden in a subclass. It is also the only realistic way to do this if you have to support legacy JUnit38 classes.

Here is some code to do the custom Runner. Regarding what getAppropriateRunnerForClass might do, the way I implemented it was to have a separate annotation that tells the custom runner what to run with. The only alternative was some very brittle copy paste from the JUnit code.

private class CustomRunner implements Runner
 private Runner runner;

    public CustomRunner(Class<?> klass, RunnerBuilder builder) throws Throwable {
        if (!isRunCustomTests()) {
            runner = new IgnoredClassRunner(klass);
        } else {
            runner = getAppropriateRunnerForClass(klass, builder);
    }

    public Description getDescription() {
        return runner.getDescription();
    }

    public void run(RunNotifier notifier) {
        runner.run(notifier);
    }
}

EDIT: The @RunWith tag only works for a whole class. One way to work around that limiation is to move the test methods into a static inner class and annotate that. That way you have the advantage of the annotation with the organization of the class. But, doing that won't help with any @Before or @BeforeClass tags, you will have to recreate those in the inner class. It can call the outer class's method, but it would have to have its own method as a hook.