Package: rubygem-rspec

"rubygem-rspec" package binaries on CentOS:

/usr/bin/autospec /usr/bin/spec /usr/lib/ruby/gems/1.8/gems/rspec-1.3.0/bin/autospec /usr/lib/ruby/gems/1.8/gems/rspec-1.3.0/bin/spec

You may install this package on CentOS with yum install rubygem-rspec