public static void checkSingleChar(final Properties props, final String propKey, final MaskAlgorithm<?, ?> algorithm) {
        checkRequired(props, propKey, algorithm);
        ShardingSpherePreconditions.checkState(1 == props.getProperty(propKey).length(), () -> new AlgorithmInitializationException(algorithm, "%s's length must be one", propKey));
    }
@Test
    void assertCheckSingleCharFailedWithMultipleChars() {
        Properties props = PropertiesBuilder.build(new Property("key", "111"));
        assertThrows(AlgorithmInitializationException.class, () -> MaskAlgorithmPropertiesChecker.checkSingleChar(props, "key", mock(MaskAlgorithm.class)));
    }