tests that product doesn't move or copy elements
tests that product doesn't move or copy elements

ryanhaining/cppitertools,ryanhaining/cppitertools,tempbottle/cppitertools,tempbottle/cppitertools,jkhoogland/cppitertools,tempbottle/cppitertools,jkhoogland/cppitertools,ryanhaining/cppitertools,jkhoogland/cppitertools