add a test for ryu.lib.stringify
add a test for ryu.lib.stringify

Signed-off-by: YAMAMOTO Takashi <458bba2e4a8704776b33478100c98529b639cd9e@valinux.co.jp>
Signed-off-by: FUJITA Tomonori <93dac1fe9c4b2a3957982200319981492ad4976e@lab.ntt.co.jp>

Tejas-Subramanya/RYU_MEC,fkakuma/ryu,openvapour/ryu,osrg/ryu,umkcdcrg01/ryu_openflow,lzppp/mylearning,StephenKing/ryu,yamt/ryu,umkcdcrg01/ryu_openflow,gareging/SDN_Framework,citrix-openstack-build/ryu,ysywh/ryu,openvapour/ryu,pichuang/ryu,jalilm/ryu,diogommartins/ryu,gareging/SDN_Framework,yamt/ryu,John-Lin/ryu,openvapour/ryu,John-Lin/ryu,pichuang/ryu,gopchandani/ryu,castroflavio/ryu,Zouyiran/ryu,lagopus/ryu-lagopus-ext,ttsubo/ryu,jalilm/ryu,shinpeimuraoka/ryu,yamt/ryu,hisaharu/ryu,StephenKing/ryu,habibiefaried/ryu,alyosha1879/ryu,o3project/ryu-oe,iwaseyusuke/ryu,evanscottgray/ryu,Tesi-Luca-Davide/ryu,lsqtongxin/ryu,Tesi-Luca-Davide/ryu,ttsubo/ryu,torufuru/OFPatchPanel,ntts-clo/mld-ryu,John-Lin/ryu,torufuru/oolhackathon,citrix-openstack/build-ryu,fujita/ryu,alanquillin/ryu,ynkjm/ryu,iwaseyusuke/ryu,lagopus/ryu-lagopus-ext,osrg/ryu,gopchandani/ryu,haniehrajabi/ryu,iwaseyusuke/ryu,hisaharu/ryu,diogommartins/ryu,ysywh/ryu,iwaseyusuke/ryu,samrussell/ryu,habibiefaried/ryu,zangree/ryu,diogommartins/ryu,jalilm/ryu,OpenState-SDN/ryu,darjus-amzn/ryu,muzixing/ryu,shinpeimuraoka/ryu,John-Lin/ryu,unifycore/ryu,shinpeimuraoka/ryu,o3project/ryu-oe,jkoelker/ryu,habibiefaried/ryu,John-Lin/ryu,fkakuma/ryu,jalilm/ryu,torufuru/OFPatchPanel,lagopus/ryu-lagopus-ext,fujita/ryu,sivaramakrishnansr/ryu,TakeshiTseng/ryu,darjus-amzn/ryu,elahejalalpour/ELRyu,alanquillin/ryu,castroflavio/ryu,OpenState-SDN/ryu,haniehrajabi/ryu,jazzmes/ryu,muzixing/ryu,alanquillin/ryu,ntts-clo/ryu,StephenKing/summerschool-2015-ryu,gareging/SDN_Framework,openvapour/ryu,StephenKing/summerschool-2015-ryu,pichuang/ryu,zangree/ryu,citrix-openstack-build/ryu,yamada-h/ryu,lsqtongxin/ryu,TakeshiTseng/ryu,StephenKing/ryu,umkcdcrg01/ryu_openflow,muzixing/ryu,torufuru/oolhackathon,lagopus/ryu-lagopus-ext,takahashiminoru/ryu,ttsubo/ryu,castroflavio/ryu,umkcdcrg01/ryu_openflow,ysywh/ryu,pichuang/ryu,gopchandani/ryu,openvapour/ryu,lsqtongxin/ryu,gareging/SDN_Framework,OpenState-SDN/ryu,fujita/ryu,yamada-h/ryu,TakeshiTseng/ryu,iwaseyusuke/ryu,sivaramakrishnansr/ryu,alyosha1879/ryu,habibiefaried/ryu,gareging/SDN_Framework,torufuru/oolhackathon,Tejas-Subramanya/RYU_MEC,takahashiminoru/ryu,zangree/ryu,jalilm/ryu,yamt/ryu,StephenKing/summerschool-2015-ryu,alyosha1879/ryu,unifycore/ryu,zyq001/ryu,darjus-amzn/ryu,citrix-openstack/build-ryu,darjus-amzn/ryu,ysywh/ryu,fkakuma/ryu,OpenState-SDN/ryu,Tesi-Luca-Davide/ryu,ynkjm/ryu,jkoelker/ryu,gopchandani/ryu,mikhaelharswanto/ryu,ttsubo/ryu,darjus-amzn/ryu,evanscottgray/ryu,StephenKing/summerschool-2015-ryu,osrg/ryu,sivaramakrishnansr/ryu,lzppp/mylearning,zangree/ryu,pichuang/ryu,osrg/ryu,StephenKing/ryu,umkcdcrg01/ryu_openflow,elahejalalpour/ELRyu,Tesi-Luca-Davide/ryu,Zouyiran/ryu,fkakuma/ryu,ynkjm/ryu,lagopus/ryu-lagopus-ext,zyq001/ryu,takahashiminoru/ryu,elahejalalpour/ELRyu,diogommartins/ryu,OpenState-SDN/ryu,zyq001/ryu,samrussell/ryu,fujita/ryu,evanscottgray/ryu,Zouyiran/ryu,lzppp/mylearning,Tesi-Luca-Davide/ryu,TakeshiTseng/ryu,elahejalalpour/ELRyu,Zouyiran/ryu,alyosha1879/ryu,elahejalalpour/ELRyu,muzixing/ryu,ynkjm/ryu,haniehrajabi/ryu,zyq001/ryu,ysywh/ryu,lzppp/mylearning,gopchandani/ryu,osrg/ryu,muzixing/ryu,hisaharu/ryu,haniehrajabi/ryu,alanquillin/ryu,Tejas-Subramanya/RYU_MEC,shinpeimuraoka/ryu,diogommartins/ryu,fkakuma/ryu,lsqtongxin/ryu,ntts-clo/ryu,haniehrajabi/ryu,zyq001/ryu,StephenKing/summerschool-2015-ryu,alanquillin/ryu,Tejas-Subramanya/RYU_MEC,sivaramakrishnansr/ryu,yamt/ryu,habibiefaried/ryu,jazzmes/ryu,ynkjm/ryu,sivaramakrishnansr/ryu,jkoelker/ryu,zangree/ryu,hisaharu/ryu,takahashiminoru/ryu,Zouyiran/ryu,ntts-clo/mld-ryu,TakeshiTseng/ryu,Tejas-Subramanya/RYU_MEC,lzppp/mylearning,shinpeimuraoka/ryu,mikhaelharswanto/ryu,hisaharu/ryu,StephenKing/ryu,takahashiminoru/ryu,fujita/ryu,jazzmes/ryu,lsqtongxin/ryu,ttsubo/ryu