assertEquals(0, fields.length);
    }

    public void test_indexAdminRequiredFields() {
        String[] fields = fessConfig.getIndexAdminRequiredFields().split(",");
        assertEquals(4, fields.length);
        assertEquals("url", fields[0]);
        assertEquals("title", fields[1]);
        assertEquals("role", fields[2]);

    }

    public void test_validateIndexRequiredFields() {
        FessProp.propMap.clear();
        FessConfig fessConfig = new FessConfig.SimpleImpl() {
            @Override
            public String getIndexAdminRequiredFields() {
                return "aaa,bbb";
            }
        };

        HashMap<String, Object> source = new HashMap<>();
        assertFalse(fessConfig.validateIndexRequiredFields(source));

                }
            }
            return new Pair<>(key, value);
        }).collect(Collectors.toMap(Pair::getFirst, Pair::getSecond));
    }

    String getIndexAdminRequiredFields();

    default boolean validateIndexRequiredFields(final Map<String, Object> source) {
        return invalidIndexRequiredFields(source).isEmpty();
    }

     * comment: Required fields for admin in the index.
     * @return The value of found property. (NotNull: if not found, exception but basically no way)
     */
    String getIndexAdminRequiredFields();

    /**
     * Get the value for the key 'index.search.timeout'. <br>
     * The value is, e.g. 3m <br>
     * comment: Timeout for index search operations.