java - Specifying an order to junit 4 tests at the Method level (not class level)

Question

I know this is bad practice, but it needs to be done, or I'll need to switch to testng. Is there a way, similar to JUnit 3's testSuite, to specify the order of the tests to be run in a class?

Answer 1

If you're sure you really want to do this: There may be a better way, but this is all I could come up with...

JUnit4 has an annotation: @RunWith which lets you override the default Runner for your tests.

In your case you would want to create a special subclass of BlockJunit4ClassRunner, and override computeTestMethods() to return tests in the order you want them executed. For example, let's say I want to execute my tests in reverse alphabetical order:

public class OrderedRunner extends BlockJUnit4ClassRunner {

    public OrderedRunner(Class klass) throws InitializationError {
        super(klass);
    }

    @Override
    protected List computeTestMethods() {
        List list = super.computeTestMethods();
        List copy = new ArrayList(list);
        Collections.sort(copy, new Comparator() {
            public int compare(FrameworkMethod o1, FrameworkMethod o2) {
                return o2.getName().compareTo(o1.getName());
            }
        });
        return copy;
    }
}

@RunWith(OrderedRunner.class)
public class OrderOfTest {
    @Test public void testA() { System.out.println("A"); }
    @Test public void testC() { System.out.println("C"); }
    @Test public void testB() { System.out.println("B"); }
}

Running this test produces:

C
B
A

For your specific case, you would want a comparator that would sort the tests by name in the order you want them executed. (I would suggest defining the comparator using something like Google Guava's class Ordering.explicit("methodName1","methodName2").onResultOf(...); where onResultOf is provided a function that converts FrameworkMethod to its name... though obviously you are free to implement that any way you want.