xstress is a tool developed by me, that allows users to stress test (their) SMTP Mail servers. The tool is pretty straight forward (and very simple too). It creates multiple connections to the mail server and pumps e-mail traffic on those connection. That’s it.
The good thing is that you can configure lots of parameter to simulate different kind of traffic, like virus traffic and spam traffic for instance.
You may use the links below to get sample (un-harmful) virus file and spam file respectively.
http://en.wikipedia.org/wiki/EICAR_test_file
http://en.wikipedia.org/wiki/GTUBE
The tool contains a README file explaining how to build and run it.
Complete source is available at the following link: http://sourceforge.net/projects/xstress
xstress Home Page : http://xstress.sourceforge.net
Hope this tool is useful to some ( or all 
)