@Override
    public <V1, R> KTable<K, R> leftJoin(final KTable<K, V1> other,
                                         final ValueJoiner<? super V, ? super V1, ? extends R> joiner) {
        return leftJoin(other, joiner, NamedInternal.empty());
    }
@Test
    public void shouldNotAllowNullOtherTableOnLeftJoin() {
        assertThrows(NullPointerException.class, () -> table.leftJoin(null, MockValueJoiner.TOSTRING_JOINER));
    }