public LinkedHashSet<Class<?>> getRegisteredPojoTypes() {
        return registeredPojoTypes;
    }
@Test
    void testLoadingPojoTypesFromSerializationConfig() {
        String serializationConfigStr =
                "[org.apache.flink.api.common.serialization.SerializerConfigImplTest:"
                        + " {type: pojo},"
                        + " org.apache.flink.api.common.serialization.SerializerConfigImplTest$TestSerializer1:"
                        + " {type: pojo},"
                        + " org.apache.flink.api.common.serialization.SerializerConfigImplTest$TestSerializer2:"
                        + " {type: pojo}]";
        SerializerConfig serializerConfig = getConfiguredSerializerConfig(serializationConfigStr);

        assertThat(serializerConfig.getRegisteredPojoTypes())
                .containsExactly(
                        SerializerConfigImplTest.class,
                        TestSerializer1.class,
                        TestSerializer2.class);
    }