it 'should not consider as a missing attribute a value that evaluates to false' do
      subject.params do
        requires :first
        optional :false
      end

      subject.post '/declared' do
        error!('expected false', 400) if declared(params, include_missing: false)[:false] != false
        ''
      end

      post '/declared', MultiJson.dump(first: 'one', false: false), 'CONTENT_TYPE' => 'application/json'
      expect(last_response.status).to eq(201)
    end