require "spec_helper"

module Proplog
  describe Expression::Implication do
    subject { Expression::Implication.new("left", "right") }
  
    describe "#to_s" do
      it "returns the conjunction in string form" do
        expect(subject.to_s).to eq "left → right"
      end
    end
  
    describe "#premise" do
      it "returns the 'left' side of the expression" do
        expect(subject.premise).to eq subject.left
      end
    end
  
    describe "#conclusion" do
      it "returns the 'right' side of the expression" do
        expect(subject.conclusion).to eq subject.right
      end
    end
  end
end
