require 'spec_helper' describe 'Veritas::Optimizer::Algebra::Union::EmptyLeft#optimize' do subject { object.optimize } let(:klass) { Optimizer::Algebra::Union::EmptyLeft } let(:header) { Relation::Header.new([ [ :id, Integer ] ]) } let(:left) { Relation.new(header, [ [ 1 ] ].each) } let(:right) { Relation.new(header, [ [ 2 ] ].each) } let(:relation) { left.union(right) } let(:object) { klass.new(relation) } before do object.operation.should be_kind_of(Algebra::Union) end it { should equal(right) } end