There isn't a way to send a test email without meeting the criteria of the mailer as it depends on information like your subscription and in a test that information won't exist.

What you could do is create a copy of the mailer. Simplify the requirements and restrict it to only your user then run the mailer. This would let you test how the message body will display. It goes through the same mailer API as CBs mass mailer in CB > User Management though so if you're just needing to test HTML I recommend doing so using the mass mailer to email yourself.