Wait, that doesn't work if more than one role is added, as they get
merged together by the quoting.
A somewhat ugly amount of quoting can be done at the shell level to
induce double quotes.
$ createuser -g "\"test_rol'e_3\"" usequoted3
I note that similar (with not quite identical behaviour) issues apply
to the user name. Perhaps the
resolution to this is to leave quoting issues to the administrator.
That simplifies the problem away.
I suspect that the apparatus needed to do a thorough solution (e.g. -
parse the string, and do something
"smarter") may be larger than is worth getting into.