I think you missed this part 
How can I tell if Avast is working properly
Sorry. You're right Eddy.
Besides this, if the user wants to test email provider and Outlook pluggin, i.e., to see if avast! is scanning emails, checks one of these points:
1) Is the avast icon (the special one of email scanning) be shown in the system tray?
2) Is your email header with the lines
X-Antivirus: avast! (VPS 0XXX-X, XX/XX/2005), Inbound message and
X-Antivirus-Status: Clean? (Right click the message, choose Properties and Details)
To see the Standard Shield and other protection:
1) Is the 'a' blue icon swirling?
2) Right click the icon once and see what are the 'last scanned files'...
3) Use eicar virus test.
3) Are clean notes added at the bottom of the email? (Internet Mail provider settings)
You can test the security of your email system here: http://www.gfi.com/emailsecuritytest/