How to run all tests belonging to a certain Category in JUnit 4

Question

JUnit 4.8 contains a nice new feature called "Categories" that allows you to group certain kinds of tests together. This is very useful, e.g. to have separate test runs for slow and fast tests. I know the stuff mentioned in JUnit 4.8 release notes, but would like to know how I can actually run all the tests annotated with certain category.

The JUnit 4.8 release notes show an example suite definition, where SuiteClasses annotation selects the tests from certain category to run, like this:

@RunWith(Categories.class)
@IncludeCategory(SlowTests.class)
@SuiteClasses( { A.class, B.class }) // Note that Categories is a kind of Suite
public class SlowTestSuite {
  // Will run A.b and B.c, but not A.a
}

Does anyone know how I could run all the tests in SlowTests category? It seems that you must have the SuiteClasses annotation...

Answer 1

I am not sure, what exactly your problem is.

Just add all the tests to a suite (or hirachy of suites). Then use the Categories Runner and Include/ExcludeCategory annotation, to specify the categories you want to run.

A good idea might be to have one suite containing all the tests, and a couple of seperate suites referring to the first one, specifying the different set of Categories you neeed.

Answer 2

I found out one possible way to achieve what I want, but I don't consider this to be the best possible solution as it relies on ClassPathSuite library that is not part of JUnit.

I define the test suite for slow tests like this:

@RunWith(Categories.class)
@Categories.IncludeCategory(SlowTests.class)
@Suite.SuiteClasses( { AllTests.class })
public class SlowTestSuite {
}

AllTests class is defined like this:

@RunWith(ClasspathSuite.class)
public class AllTests {
}

I had to use ClassPathSuite class from ClassPathSuite project here. It will find all the classes with tests.

Answer 3

Not a direct answer to your problem, but maybe the general approach could be improved...

Why are your tests slow? Maybe the set-up lasts long (database, I/O etc.), maybe the tests are testing too much? If this is the case I would seperate the real unit-tests from the "long-running" ones, which often indeed are integration tests.

In my setups I have staging env, where unit-tests are run often and integration-tests constantly but more rarely (e.g. after each commit in version control). I have never worked with grouping for unit tests, because they should be loosely coupled alltogether. I only work with grouping and relationship of test-cases in integration-test setups (but with TestNG).

But good to know that JUnit 4.8 introduced some grouping features.