I have a user with a Google Apps mail account that forwards every mail received to another email address. I sent him an email that he says he never received. I can see that the email made it into his GA mail account, but I don't know how to determine if it was ever forwarded. Is there a way to know if the rule worked or if the email was forwarded? There was nothing in Sent Items, so I assume GA mail doesn't put forwarded email there when it's done by rule - but not sure about that.
More Info: It turns out that the email that was not being forwarded was email that was BCC'd to the recipient. The rule said to forward mail that was "To: email@example.com" but did not contemplate BCC. Nevertheless I have not found a way to determine if a mail was processed by a rule other than checking what the results would be if it were.