EICAR test virus
Test your virus checker with this email. It contains eicar.com as a file attachment. This program is completely harmless, only outputting the text
on the console. When the file is opened, an XP commandline console in which the text appears is launched. You can open or save the file without concern. Also see: www.eicar.org
Any antivirus program should identify the file as an EICAR test file, output the warning, and prevent you from executing or opening the file. If your emails are filtered at the email gateway, the virus scanner should detect the file attachment as a virus and not let the email through, at least not with the file attached.
Warning: If your provider or another mail gateway filters your emails for viruses, this email may never reach you.