fails:SystemCallError.new requires at least one argumentt
fails:SystemCallError.new takes an optional errno argument
fails:SystemCallError.new accepts single Fixnum argument as errno
fails:SystemCallError.new constructs the appropriate Errno class
fails:SystemCallError.new returns an arity of -1 for the initialize method
fails:SystemCallError#errno returns nil when no errno given
fails:SystemCallError#errno returns the errno given as optional argument to new
fails:SystemCallError#message returns the default message when no message is given
fails:SystemCallError#message returns the message given as an argument to new
