> For the complete documentation index, see [llms.txt](https://kelby.gitbook.io/rails-beginner-s-guide/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://kelby.gitbook.io/rails-beginner-s-guide/testing/testcase_actionmailer.md).

# Action Mailer

## Test Helper

默认 Rails 提供两个 helper 方法用于测试：

| 方法                           | 解释                                 |
| ---------------------------- | ---------------------------------- |
| assert\_emails               | 断言已经发送的邮件数                         |
| assert\_no\_emails           | 断言没有邮件发送出去(可用 assert\_emails 0 代替) |
| assert\_enqueued\_emails     | 断言邮件已进队列                           |
| assert\_no\_enqueued\_emails | 断言邮件不在队列里                          |

assert\_emails 和 assert\_no\_emails 两者本质都是封装 assert\_equal.

## ~~Behavior~~

类方法：

```
determine_default_mailer

mailer_class

tests
```

~~实例方法：~~

```
initialize_test_deliveries

restore_delivery_method
restore_test_deliveries

set_delivery_method
set_expected_mail
```

除通常的测试方法外，还有 `deliveries` 方法获取已经发送的邮件实例。

使用举例:

```ruby
last_email = ActionMailer::Base.deliveries.last

expect(last_email.to).to eq ['test@example.com']
expect(last_email.subject).to have_content 'Welcome'

email = UserMailer.confirmation(user.id).deliver_now

assert ActionMailer::Base.deliveries.any?
assert_equal [user.email], email.to
```


---

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