ruby - rspec newb 不明白如何满足 "before"方法

Question

这里是新手...刚刚熟悉 rspec，并有以下问题:

describe Song do

  before do
     @song = Song.new
  end

  describe 'title' do
    it 'should capitalize the first letter' do
      @song.title = "lucky"
      @song.title.should == "Lucky"
    end
end

我不知道如何满足“before do ....end” 我看到它被写在许多教程和 rspec 示例中，但我仍然不知道如何满足 ruby​​ 代码以便它能够通过。谢谢

Answer 1

RSpec 一开始可能会令人困惑，因为总是有许多有效的方法可以实现相同的目标。这就是为什么我建议您获取 The Rspec Book而不是(或之前)浏览“许多教程和示例”。

我可以轻松地为这个单一测试想出八种不同的方法(请参阅下面的代码示例)，并且您可以更多地混合和匹配其中的各个部分，从而产生更多不同的方法来解决同一问题。

这就是为什么我认为在能够完成示例和教程之前，有必要对 RSpec 原理有基本的了解 - 每个示例看起来都会略有不同，但如果您掌握了基础知识，您将很容易看到每个示例的作用。

require "rspec"

class Song
  def title=(title)
    @title = title
  end

  def title
    @title.capitalize
  end
end

describe Song do
  before { @song = Song.new }

  describe "#title" do
    it "should capitalize the first letter" do
      @song.title = "lucky"
      @song.title.should == "Lucky"
    end
  end
end

describe Song do
  describe "#title" do
    it "should capitalize the first letter" do
      song = Song.new
      song.title = "lucky"
      song.title.should == "Lucky"
    end
  end
end

describe Song do
  let(:song) { Song.new }

  describe "#title" do
    before { song.title = "lucky" }

    it "should capitalize the first letter" do
      song.title.should == "Lucky"
    end
  end
end

describe Song do
  let(:song)  { Song.new }
  subject     { song }

  before { song.title = "lucky" }

  its(:title) { should == "Lucky" }
end

describe Song do
  let(:song) { Song.new }

  describe "#title" do
    before { song.title = "lucky" }

    context "capitalization of the first letter" do
      subject { song.title }
      it { should == "Lucky" }
    end
  end
end

describe Song do
  context "#title" do
    before { subject.title = "lucky" }
    its(:title) { should == "Lucky" }
  end
end

RSpec::Matchers.define :be_capitalized do
  match do |actual|
    actual.capitalize == actual
  end
end

describe Song do
  context "#title" do
    before { subject.title = "lucky" }
    its(:title) { should be_capitalized }
  end
end

describe Song do
  let(:song) { Song.new }

  context "#title" do
    subject { song.title }
    before { song.title = "lucky" }
    it { should be_capitalized }
  end
end