The eicar test virus will trigger the 'DefaultAV' ClamAV engine when it comes into Sentry as an attachment (in a file). Sentry administrators can test this by sending the eicar test virus into Sentry as an attachment. The test file can be base64 encoded or not, compressed or not.
For more information on the eicar test virus see: http://www.eicar.org/86-0-Intended-use.html.
Sentry administrators can test the ClamAV engine with a simple string using the ClamAV test string.
The base64 encoded ClamAV test string is below.. (encoded so it gets through the mail filters).
You can decode this to get the actual string here: http://www.base64encode.org/