You can test proper operability of anti-virus programs detecting viruses by their signatures with the use of EICAR (European Institute for Computer Anti-Virus Research) file.
This program is specially designed to allow you to see how the installed anti-virus will alert you to the viruses it detected, with no need to expose your PC to danger. Eicar program is not malicious but is specially tuned so that most anti-viruses treat it as a virus. Dr.Web refers to this “virus” as EICAR Test File (Not a Virus!).
To test mail anti-virus performance, you can ask a friend of yours to send you this file, or otherwise try to send it to yourself. If SpIDer Mail detects a virus — that is OK.