# encoding: utf-8 require 'spec_helper' describe Optimizer::Algebra::Rename::EmptyOperand, '#optimizable?' do subject { object.optimizable? } let(:header) { Relation::Header.coerce([[:id, Integer]]) } let(:relation) { operand.rename(id: :other_id) } let(:object) { described_class.new(relation) } before do expect(object.operation).to be_kind_of(Algebra::Rename) end context 'when the operand is an empty relation' do let(:operand) { Relation::Empty.new(header) } it { should be(true) } end context 'when the operand is not an empty relation' do let(:operand) { Relation.new(header, [[1]]) } it { should be(false) } end end