優雅的 RSpec 測試 - 物件的可測試性

 1class Worker
 2  attr_accessor :stopped
 3
 4  def initialize(stopped: true)
 5    @stopped = stopped
 6  end
 7
 8  def start
 9    @stopped = false
10  end
11
12  def stop
13    @stopped = true
14  end
15
16  def stop?
17    @stopped == true
18  end
19end

 1RSpec.describe Worker do
 2  subject(:worker) { Worker.new }
 3
 4  it { is_expected.to be_stop }
 5
 6  describe '#start' do
 7    before { worker.start }
 8
 9    it { is_expected.not_to be_stop }
10  end
11
12  describe '#stop' do
13    subject(:worker) { Worker.new(stoppted: false) }
14
15    before { worker.stop }
16
17    it { is_expected.to be_stop }
18    it { expect { worker.stop }.to change(worker, :stopped).from(false).to(true) }
19  end
20end

 1class Subscription
 2  attr_reader :services
 3
 4  def active(service_name)
 5    return false if activated?
 6
 7    append_service(name: service_name)
 8  end
 9
10  private
11
12  def append_service(name:)
13    return @services if @services.include?(name)
14
15    @services += [name]
16  end
17end

 1RSpec.describe Subscription do
 2  # ...
 3  describe '#active' do
 4    subject(:active) { subscription.active('unlimited_reader') }
 5
 6    it { is_expected.to be_falsy }
 7
 8    context 'when subscription is actived' do
 9      # ...
10
11      it { is_expected.to include('unlimited_reader') }
12    end
13
14    context 'when subscription is actived and activated unlimited_reader' do
15      before { subscription.active('unlimited_reader') }
16
17      it { is_expected.to include('unlimited_reader') }
18    end
19  end
20end