}
            });

            assertEquals(hostname, ComponentUtil.getFessConfig().getMailHostname());
        }
    }

    // Test with null values
    public void test_nullValues() {
        ComponentUtil.setFessConfig(new FessConfig.SimpleImpl() {
            private static final long serialVersionUID = 1L;

            @Override
            public String getMailFromName() {

        assertTrue(docMap.containsValue("value1"));
        assertTrue(docMap.containsValue(null));
        assertFalse(docMap.containsValue("nonexistent"));
    }

    public void test_null_values() {
        Map<String, Object> parentMap = new HashMap<>();
        DocMap docMap = new DocMap(parentMap);

        docMap.put("nullKey", null);
        assertTrue(docMap.containsKey("nullKey"));