blowmage/minitest-rails — pull request #65 by haihappen (2012-07-26 13:34:14+00:00)
Title: Load ActionMailer only if it is also used.

I have Rails app which will never use `ActionMailer`, so I excluded `ActionMailer` at all:

```ruby
require 'active_record/railtie'
require 'action_controller/railtie'
# require 'action_mailer/railtie'
# require 'active_resource/railtie'
# require 'rails/test_unit/railtie'
require 'sprockets/railtie'
```

This commit fixes specs failing with `uninitialized constant ActionMailer::TestCase::Behavior::TestHelper (NameError)`.