io.directories: Add unit test for #890.
io.directories: Add unit test for #890.

slavapestov/factor,slavapestov/factor,factor/factor,nicolas-p/factor,mrjbq7/factor,nicolas-p/factor,mrjbq7/factor,factor/factor,bpollack/factor,AlexIljin/factor,slavapestov/factor,factor/factor,bpollack/factor,mrjbq7/factor,sarvex/factor-lang,mrjbq7/factor,AlexIljin/factor,bjourne/factor,slavapestov/factor,tgunr/factor,sarvex/factor-lang,nicolas-p/factor,slavapestov/factor,tgunr/factor,sarvex/factor-lang,tgunr/factor,bpollack/factor,bpollack/factor,bjourne/factor,dch/factor,slavapestov/factor,tgunr/factor,dch/factor,tgunr/factor,bjourne/factor,slavapestov/factor,dch/factor,AlexIljin/factor,bjourne/factor,AlexIljin/factor,dch/factor,bpollack/factor,sarvex/factor-lang,mrjbq7/factor,nicolas-p/factor,mrjbq7/factor,dch/factor,bpollack/factor,bjourne/factor,factor/factor,AlexIljin/factor,dch/factor,nicolas-p/factor,sarvex/factor-lang,nicolas-p/factor,AlexIljin/factor,sarvex/factor-lang,nicolas-p/factor,AlexIljin/factor,sarvex/factor-lang,bjourne/factor,factor/factor,factor/factor,tgunr/factor,bpollack/factor,bjourne/factor