require 'spec_helper' describe Algebra::Projection, '#directions' do subject { object.directions } let(:relation) { Relation.new([ [ :id, Integer ], [ :name, String ] ], [ [ 1, 'Dan Kubb' ] ]) } let(:object) { described_class.new(operand, [ :id ]) } context 'containing an unordered relation' do let(:operand) { relation } it_should_behave_like 'an idempotent method' it { should equal(Relation::Operation::Order::DirectionSet::EMPTY) } end context 'containing an ordered relation' do let(:operand) { relation.order } it_should_behave_like 'an idempotent method' it { should equal(Relation::Operation::Order::DirectionSet::EMPTY) } end end