fails:ARGF.gets reads one line of a file
fails:ARGF.gets reads all lines of a file
fails:ARGF.gets reads all lines of stdin
fails:ARGF.gets reads all lines of two files
fails:ARGF.gets sets $_ global variable with each line read
fails:ARGF.gets modifies the files when in place edit mode is on
fails:ARGF.gets modifies and backups two files when in place edit mode is on
fails:ARGF.gets returns nil when reaching end of files
fails:ARGF.gets reads the contents of the file with default encoding
