file-roller just didn't include rar password support and the testing of archives
up until now. But it easily can (patch attached) although it isn't obvious from
the rar documentation that you can pass rar a password via the -p switch when
extracting or testing an archive.

The caveats are: 

1) if both, the headers and the data of an rar archive are encrypted, even the
listing of the archive fails. 

2) if the password is wrong, a dialog is shown, but it doesn't contain any
output from the command line.


Also, I just changed the file name processing for rar archives. If listing an
rar archive the file name is on a line by its own, but the first character of
that line is an indicator which should be ignored whereas the file name is on
the rest of the line (including any white spaces at the end). If the indicator
character is an asterisk it means the file is encrypted.

I tested it with rar 3.30 and 2.80; and unrar 3.40.