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: johndoe@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.
Best Answer
If you don't have access to the receiving account, you could change the rule to forward to an address you have access to, test it, and then change it back. Remember, gmail doesn't forward an email back to the sender, so you can't send from a@b.com and hope to receive it at a@b.com.