testRule.setResponseProcessor(null);
        assertNull(testRule.getResponseProcessor());
    }

    /**
     * Test register method with index 0
     */
    public void test_register_indexZero() {
        testRule.setRuleId("rule1");

        // Pre-add some rules
        TestAbstractRule existingRule = new TestAbstractRule();
        existingRule.setRuleId("existing");