fail("Should throw ConfigPropertyNotFoundException");
        } catch (ConfigPropertyNotFoundException e) {
            assertTrue(e.getMessage().contains("non.existent.property"));
        }

        try {
            emptyEnv.is("non.existent.boolean");
            fail("Should throw ConfigPropertyNotFoundException");
        } catch (ConfigPropertyNotFoundException e) {

                case "filter.null":
                    // This would be filtered to null by PropertyFilter in real scenario
                    throw new ConfigPropertyNotFoundException("filter.null");
                default:
                    throw new ConfigPropertyNotFoundException(propertyKey);
                }
            }
        };

        ComponentUtil.register(fessConfig, "fessConfig");
    }

    @Override

     * @throws ConfigPropertyNotFoundException When the property is not found.
     */
    String get(String propertyKey);

    /**
     * Is the property true?
     * @param propertyKey The key of the property which is boolean type. (NotNull)
     * @return The determination, true or false. (if not found, exception)
     * @throws ConfigPropertyNotFoundException When the property is not found.
     */

    @Test
    public void test_propertyNotFound() {
        try {
            fessConfig.get("non.existent.property");
            fail("Should throw ConfigPropertyNotFoundException");
        } catch (ConfigPropertyNotFoundException e) {
            assertEquals("non.existent.property", e.getMessage());
        }
    }

    // Test isExtensionAllowed method
    /*

     * @throws ConfigPropertyNotFoundException When the property is not found.
     */
    String get(String propertyKey);

    /**
     * Is the property true?
     * @param propertyKey The key of the property which is boolean type. (NotNull)
     * @return The determination, true or false. (if not found, exception)
     * @throws ConfigPropertyNotFoundException When the property is not found.
     */