How to define a JUnit method rule in a test suite?

Question

I have a class that is a JUnit suite of JUnit test classes. I would like to define a rule on the suite to do something to the database before and a

Answer 1

This can be done, but it needs a bit of work. You need to define your own Suite runner and your own Test runner as well, and then override runChild() in the test runner. Using the following:

AllTests.java:

@RunWith(MySuite.class)
@SuiteClasses({Class1Test.class})
public class AllTests {
}

Class1Test.java:

public class Class1Test {
    @Deprecated @Test public void test1() {
        System.out.println("" + this.getClass().getName() + " test1");
    }

    @Test public void test2() {
        System.out.println("" + this.getClass().getName() + " test2");
    }
}

Note that I've annotated test1() with @Deprecated. You want to do something different when you have the @Deprecated annotation on the test, so we need to extend Suite to use a custom Runner:

public class MySuite extends Suite {
    // copied from Suite
    private static Class[] getAnnotatedClasses(Class klass) throws InitializationError {
        Suite.SuiteClasses annotation = klass.getAnnotation(Suite.SuiteClasses.class);
        if (annotation == null) {
            throw new InitializationError(String.format("class '%s' must have a SuiteClasses annotation", klass.getName()));
        }
        return annotation.value();
    }

    // copied from Suite
    public MySuite(Class klass, RunnerBuilder builder) throws InitializationError {
        super(null, getRunners(getAnnotatedClasses(klass)));
    }

    public static List getRunners(Class[] classes) throws InitializationError {
        List runners = new LinkedList();

        for (Class klazz : classes) {
            runners.add(new MyRunner(klazz));
        }

        return runners;
    }
}

JUnit creates a Runner for each test it will run. Normally, Suite would just create the default BlockJUnit4ClassRunner, all we're doing here is overriding the constructor for the Suite which reads the classes from the SuiteClass annotation and we're creating our own runners with them, MyRunner. This is our MyRunner class:

public class MyRunner extends BlockJUnit4ClassRunner {
    public MyRunner(Class klass) throws InitializationError {
        super(klass);
    }

    @Override
    protected void runChild(final FrameworkMethod method, RunNotifier notifier) {
        Description description= describeChild(method);
        if (method.getAnnotation(Ignore.class) != null) {
            notifier.fireTestIgnored(description);
        } else {
            if (description.getAnnotation(Deprecated.class) != null) {
                System.out.println("name=" + description.getMethodName() + " annotations=" + description.getAnnotations());
            }
            runLeaf(methodBlock(method), description, notifier);
        }
    }
}

Most of this is copied from BlockJUnit4ClassRunner. The bit I've added is:

if (description.getAnnotation(Deprecated.class) != null) {
    System.out.println("name=" + description.getMethodName() + " annotations=" + description.getAnnotations());
}

where we test for the existence of the @Deprecated annotation on the method, and do something if it's there. The rest is left as an exercise for the reader. When I run the above Suite, I get as output:

name=test1 annotations=[@java.lang.Deprecated(), @org.junit.Test(expected=class org.junit.Test$None, timeout=0)]
uk.co.farwell.junit.run.Class1Test test1
uk.co.farwell.junit.run.Class1Test test2

Please note that Suite has multiple constructors depending upon how it is invoked. The above works with Eclipse, but I haven't tested other ways of running the Suite. See the comments alongside the various constructors for Suite for more information.