The macports build of tsung is currently failing here because the SVN checkout is from an HTTPS url with an invalid certificate. I've submitted a Portfile change to use the HTTP tarball, which fixes the problem.
To use, download that Portfile and put it in a clean directory, download that patch file and put it in a “files” subdirectory off where you put the Portfile. In a console, change into the Portfile directory, and
sudo port -D . install