rails/rails — pull request #16571 by lucasmazza (2014-08-20 02:28:19+00:00)
Title: Add `set_delivery_method` and `restore_delivery_method` to `ActionMailer::TestCase.

This way these methods are available outside the ActionMailer test suite, but
they are still duplicated inside `test/abstract_unit` for test cases that don't
inherit from the `ActionMailer::TestCase` class.