Add unit test for named_value of optional
Add unit test for named_value of optional

pfi/pficommon,pfi/pficommon,retrieva/pficommon,takei-yuya/pficommon,takei-yuya/pficommon,takei-yuya/pficommon,retrieva/pficommon,pfi/pficommon,retrieva/pficommon,takei-yuya/pficommon,pfi/pficommon,retrieva/pficommon,retrieva/pficommon