Rails – How to test that ActionMailer sent a specific attachment?

Here’s an example that I copied from my rspec test of a specific attachment, hope that it helps (mail can be creating by calling your mailer method or peeking at the deliveries array after calling .deliver):

  mail.attachments.should have(1).attachment
  attachment = mail.attachments[0]
  attachment.should be_a_kind_of(Mail::Part)
  attachment.content_type.should be_start_with('application/ics;')
  attachment.filename.should == 'event.ics'