[Guides states it's to be avoided][1]. I don't prefer it based on it's lack of specificity.

Consider this approach:
```ruby
describe EventInviter, '#send_invitations' do
  it 'calls invite on each invitation' do
    invitation_stub = stub('invitation', :invite)
    Invitation.stubs(:new).returns(invitation_stub)

    ..

    expect(Invitation).to have_received(:new).twice
    expect(invitation_stub).to have_received(:invite).twice
  end
end
```
[1]: https://github.com/thoughtbot/guides/tree/master/best-practices#testing
[2]: https://github.com/yammer/sched.do/blob/master/spec/models/invitee_builder_spec.rb#L32-L33