if you commented out this line (and any other line that squawks)...

> @expected.parts << body_part # <=== ERROR HERE

and printed out the mail's parts before asserting them...

> mail = Notifier.create_notification()

p mail.parts

...what would you see?

We TDD e-mails all the time, but we don't write huge bulk assertions. Sometimes
to test_first_, we cheat a little, write the correct code, print out what it
does, and then write assertions which trap the important details.

To test-first, when you need to change a mail, you clone that test, change the
input, change the assertions to expect different output, fail the test, then
pass it in the code. This shows how cheating, especially in high-bandwidth
situations like GUIs, can lead to better TDD...

--
Phlip