Perl, Python and Ruby are all excellent languages IMHO.
All three have excellent testing tools and thriving QA communities.
As a testing/QA professional, familiarity with all three couldn't do you any harm.
In case it helps convince you that Perl is not dying, notice the top eleven languages from the latest Tiobe Index of Programming Languages:
Dec Dec Delta
2011 2010 Language Rating Dec 2010 Status
1 1 Java 17.561% -0.44% A
2 2 C 17.057% +0.98% A
3 3 C++ 8.252% -0.76% A
4 5 C# 8.205% +1.52% A
5 8 Objective-C 6.805% +3.56% A
6 4 PHP 6.001% -1.51% A
7 7 (Visual) Basic 4.757% -0.36% A
8 6 Python 3.492% -2.99% A
9 9 Perl 2.472% +0.14% A
10 12 JavaScript 2.199% +0.69% A
11 11 Ruby 1.494% -0.29% A
Perl increased (+0.14%) in the past year,
while Python (-2.99%) and Ruby (-0.29%) both decreased.
In any case, Tiobe rates all three as safe-to-adopt "A Grade" languages.
I agree.
As for QA and Testing, Perl has excellent testing tools, a long
tradition of testing (automated tests have been bundled with Perl
since version 1.0 over twenty years ago) and a very talented and
active QA community, notably the
CPAN testers and
qa.perl.org --
a lot of their current work is done on the perl-qa mailing list and at
annual perl qa hackathons.