Allow checked mailer recipients to also include bcc and cc emails

[andyklimczak]

We've run into a few instances where we'd like to check the bcc and cc emails

• Change checked recipients from only the mailer's .to recipient, to also check other recipients (.bcc, .cc)
• Add new helper methods have_received_bcc_email and have_received_cc_email

[aaackerman]

What do you think about having more explicit expectations around this? I'm imagining something like this. Would this result in any false positives where we meant to send someone as the main to but instead sent it as bcc?

expect(user).to have_received_email(subject: "Subject")
expect(user).to have_received_cc_email(subject: "Subject")
expect(user).to have_received_bcc_email(subject: "Subject")

[andyklimczak]

I like that approach, it's specifies the user email and the method that the email should be sent. I'll code it up

[aaackerman]

The updates look great!

[aaackerman]

Would you mind adding a small update to the usage section explaining that there are two additional methods? https://github.com/contently/action_mailer_matchers#usage

[andyklimczak]

Will do!

[andyklimczak]

Added examples to the README and squashed ⛄️

[aaackerman]

Awesome addition, thank you!!! 🚢 I'm not sure if we have to do anything to cut a new version in rubygems?

[andyklimczak]

I had one more change that I messed up with rebasing that I just force pushed (the expected var is only defined inside of matcher, so it must be passed to be accessed outside)
I set my Gemfile to look for this gem locally using this branch (using gem "action_mailer_matchers", path: "/tmp/action_mailer_matchers"), and triple verified that the new methods work in our test suite

I think we'll have to follow the steps in this guide to publish a new version. Did you originally push the gem to rubygems?

I don't have write permissions on this repo too, so I can't merge this PR

[andyklimczak]

One more force push to correct commit message

[aaackerman]

Thanks! I tested locally too, will merge and cut a new version.