# encoding: utf-8

require 'spec_helper'

describe Algebra::Extension, '#header' do
  subject { object.header }

  let(:operand)    { Relation.new([[:id, Integer]], [[1], [2]]) }
  let(:extensions) { { test: ->(tuple) { 1 } }                  }
  let(:object)     { described_class.new(operand, extensions)   }

  it_should_behave_like 'an idempotent method'

  it { should be_instance_of(Relation::Header) }

  it { should == [[:id, Integer], [:test, Object]] }
end