@Override
    public KTable<K, V> toTable() {
        return toTable(NamedInternal.empty(), Materialized.with(keySerde, valueSerde));
    }
@Test
    public void shouldNotAllowNullMaterializedOnToTable() {
        final NullPointerException exception = assertThrows(
            NullPointerException.class,
            () -> testStream.toTable((Materialized<String, String, KeyValueStore<Bytes, byte[]>>) null));
        assertThat(exception.getMessage(), equalTo("materialized can't be null"));
    }