add test with nested form but empty model to address #67 and #70
add test with nested form but empty model to address #67 and #70

trailblazer/reform,gdott9/reform,swifthand/reform,francirp/reform,eljojo/reform,bolshakov/reform,Miralaw/reform,mipearson/reform,prosanelli/reform,prosanelli/reform,francirp/reform,simonc/reform,eljojo/reform,bolshakov/reform,halan/reform,joealba/reform,swifthand/reform,mipearson/reform,joealba/reform,apotonick/reform,Miralaw/reform,halan/reform