For an assertion like:

```ruby
it { should_not accept_values_for(:email, nil, " ", "john") }
```

the error message would show:

```
expected to reject values: [nil, " ", "john", "john@example.com"]
                 rejected: [nil, " ", "john"]
```

Are you suggesting the following error message instead?

```
expected to reject values: [nil, " ", "john", "john@example.com"]
                 accepted: ["john@example.com"]
```