After configuring rss2email for the first time, it would be nice to be able to test that it is able to send email (i.e. I configured the right SMTP credentials, there is no incompatibility with my mail provider, my hosting provider is not blocking SMTP ports, etc).

Right now, it seems like I must manually edit ~/.local/share/rss2email.json and remove one of the seen posts in a feed (and delete the etag) so as to be able to generate a test email. It would be handy to instead have a simple r2e test command that could generate an email to the default address, so the user can see that they have things configured properly.