@Test(expected=UnsupportedOperationException.class)
    public void testOverriddenSubscribeInvalid3() {
        createSubscriber().subscribe(null, null, "");
    }
Test cases for the "generic" (class-less) subscription mechanism.

@author Ulf Lilleengen
config/src/test/java/com/yahoo/config/subscription/GenericConfigSubscriberTest.java