In JUnit 3, test suites are indicated by the suite() method. In JUnit 4, suites are indicated through the @RunWith(Suite.class) annotation. Example:
public class BadExample extends TestCase{

    public static Test suite(){
    	return new Suite();
    }
}

@RunWith(Suite.class)
@SuiteClasses( { TestOne.class, TestTwo.class })
public class GoodTest {
}