* Make omniauth controller specs more robust by using shared examples for all authentication providers in controller spec. – Still passing. Yay!
* Return "casuser", instead of "casuser@" when no cas_domainname is configured.
* If no cas_domainname is configured, the CAS authentication would return "casuser@" for the users email field, because it tried to assume the email adress of the CAS user by it's username + cas_domainname.
Now it just returns the username instead of adding an "@" if cas_domainname is not configured.
This especially makes sense on CAS setups where the username equals the users email adress.
The old behaviour, if cas_domainname is configured, was not changed.
* Fetch the email from CAS attributes if provided
If the cas:authenticationSuccess (handled via omniauth-cas) response gives us an email use that.
If not, behave as before (username or username@cas_domainname).
* Fetch the (full) name from CAS attributes if provided
If the CAS response by omniauth provides a [:info][:name] field, prefer this over the uid, because we want the name to be a "Full Name", instead of just a "shortname"
