assertEquals(0, mockConfig.getApiPingEsFieldSet().size());
    }

    @Test
    public void test_fullFieldSet() {
        // Test with full field set
        Set<String> fieldSet = createFullFieldSet();

        FessConfig mockConfig = new FessConfig.SimpleImpl() {
            private static final long serialVersionUID = 1L;

            @Override
            public Set<String> getApiPingEsFieldSet() {