Since our test object is different in this case, we could define a new `let` declaration here to override our previous one:

```ruby
let(:message) { Message.new }
```

Then, the test would look like this:

```ruby
message.deliver! sending: sender, receiving: recipient
```

As its written, we're saying that evaluating the boolean expression `message.body == nil!` will throw an error, which it shouldn't.