I've come to use a nice gem called mail_view for visual testing of email templates in Rails.
I think it is totally legit and desirable to re-use that code in the views testing suite, so here we go:
(provided that your
MailView's subclass is
MailPreview, put this in
This just checks for the lack of exceptions and any content, but it's a starting point.
p.s. A nice complementary pull request of mine is here.