factory_girl

https://github.com/thoughtbot/factory_girl

Ruby

A library for setting up Ruby objects as test data.

Mail::Message#message_id=

Sets the Message-ID. Note, per RFC 2822 the Message ID consists of what is INSIDE
the < > usually seen in the mail header, so this method will return only what is inside.

 mail.message_id = '<[email protected]>'
 mail.message_id #=> '[email protected]'

Source | Google | Stack overflow

Edit

git clone [email protected]:thoughtbot/factory_girl.git
cd factory_girl
open

Contribute

# Make a new branch

git checkout -b -your-name--update-docs-Mail--Message-message_id--for-pr

# Commit to git

git add git commit -m "better docs for Mail::Message#message_id="

# Open pull request

gem install hub # on a mac you can `brew install hub`

hub fork

git push <your name> -your-name--update-docs-Mail--Message-message_id--for-pr

hub pull-request

# Celebrate!