Command Spec

command.rb

require 'command'

describe Command do
  let(:instance) { described_class.new(input, robotic_rover) }

  let(:robotic_rover) do
    instance_double(
      "RoboticRover",
      position: '0 0 N',
      move: '0 1 N',
      right_turn: '0 0 E',
      left_turn: '0 0 W'
    )
  end

  describe '#position_change' do
    subject(:position_change) { instance.position_change }

    context 'when advance command' do
      let(:input) { 'M' }

      it 'alters a rovers position' do
        expect(position_change).to eq robotic_rover.move
      end
    end

    context 'when right command' do
      let(:input) { 'R' }

      it 'alters a rovers direction' do
        expect(position_change).to eq robotic_rover.right_turn
      end
    end

    context 'when left command' do
      let(:input) { 'L' }

      it 'alters the rovers direction' do
        expect(position_change).to eq robotic_rover.left_turn
      end
    end
  end
end