io.files: make tests not use temp-file
io.files: make tests not use temp-file

mrjbq7/factor,nicolas-p/factor,factor/factor,AlexIljin/factor,factor/factor,bpollack/factor,tgunr/factor,bjourne/factor,nicolas-p/factor,AlexIljin/factor,tgunr/factor,AlexIljin/factor,nicolas-p/factor,factor/factor,tgunr/factor,bpollack/factor,bpollack/factor,mrjbq7/factor,nicolas-p/factor,nicolas-p/factor,bjourne/factor,nicolas-p/factor,bpollack/factor,bjourne/factor,bjourne/factor,AlexIljin/factor,factor/factor,tgunr/factor,tgunr/factor,factor/factor,bpollack/factor,mrjbq7/factor,mrjbq7/factor,AlexIljin/factor,nicolas-p/factor,factor/factor,AlexIljin/factor,bpollack/factor,mrjbq7/factor,mrjbq7/factor,AlexIljin/factor,bjourne/factor,tgunr/factor,bjourne/factor,bpollack/factor,bjourne/factor