Another variation

```ruby
let(:representor_hash) { {doc: 'something' } }
let(:subject) { Representor.new(@representor_hash || representor_hash) }

describe '#attributes' do
  it 'returns a hash of attributes associated with the represented resource' do
     subject.attributes.should == representor_hash
  end

  it 'returns an empty hash when no semantics are specified' do
    @represntor_hash = representor_hash.merge(...)
    subject.attributes.should be_empty
  end
end
```