rspec/rspec-rails — pull request #648 by ywen (2012-12-03 14:23:27+00:00)
Title: Check for the arity

I have an active resource model with test.

```ruby
expect(model).to have(1).error_on(:email)
```

Before 2.12.0 it works.

But not with 2.12.0. error message:

```bash
ArgumentError:
wrong number of arguments (1 for 0)

```

failed on:

```rspec/rails/extensions/active_record/base.rb```

```ruby
43 self.valid?(options[:context])
```

ActiveRecord valid? takes one param but not ActiveResource's ```valid?``` method.