Question

以下是一个用例示例，我们正在测试以确保DinnerTable#arrange仅在安排来宾时调用另一个方法DinnerTable#moar_chairs

describe DinnerTable do
  subject(:table) { DinnerTable.new }

  describe "#arrange" do
    context "when arranging for family" do
      let(:group) { :family }
      it "doesn't get extra chairs" do
        expect(table).not_to receive(:moar_chairs)
        table.arrange(group)
      end
    end

    context "when arranging for guests" do
      let(:group) { :guests }
      it "gets extra chairs" do
        expect(table).to receive(:moar_chairs)
        table.arrange(group)
      end
    end
  end
end

注意上下文如何设置要为（家庭或客人）安排的组，但是我们仍然只是在每个示例中独立调用相关方法arrange（使上下文有点无意义）。

通常将该方法放在before块中是有效的，因为大多数匹配器都期望当前可测试的条件，但是因为我们正在使用receive匹配器，预计将来会发生某些事情，我们不能那样做，否则测试就会失败。将它放在after块中也会失败，因为期望在执行after块之前返回false。如果我们只有某个during块会在示例结束之前运行...

describe DinnerTable do
  subject(:table) { DinnerTable.new }

  describe "#arrange" do
    during { table.arrange(group) }

    context "when arranging for family" do
      let(:group) { :family }
      it { should_not receive(:moar_chairs) }
    end

    context "when arranging for guests" do
      let(:group) { :guests }
      it { should receive(:moar_chairs) }
    end
  end
end

（或者也许可以将action或predicate称为subject？另一种选择是在让接收匹配器失败之前运行后块...但是我不知道会有什么样的其他后果。

使用receive匹配器为多个示例设置公共块是否还有其他好的模式？

Answer 1

在执行测试代码之前，需要设置receive期望值。以下内容将起作用并消除一些重复（DinnerTable类定义仅用于说明目的）：

class DinnerTable

  def arrange(group)
    moar_chairs if group == :guests 
  end

  def moar_chairs
  end

end

describe DinnerTable do
  let(:table) { DinnerTable.new }
  let(:arrange) { table.arrange(group) }

  describe "#arrange" do
    context "when arranging for family" do
      let(:group) { :family }
      it "doesn't get extra chairs" do
        expect(table).not_to receive(:moar_chairs)
        arrange
      end
    end

    context "when arranging for guests" do
      let(:group) { :guests }
      it "gets extra chairs" do
        expect(table).to receive(:moar_chairs)
        arrange
      end
    end
  end
end

Answer 2

哦，我错了！我一定是第一次做错了，因为把方法放在after块中可以工作：D Yay！

所以：

describe DinnerTable do
  subject(:table) { DinnerTable.new }

  describe "#arrange" do
    after { table.arrange(group) }

    context "when arranging for family" do
      let(:group) { :family }
      it { should_not receive(:moar_chairs) }
    end

    context "when arranging for guests" do
      let(:group) { :guests }
      it { should receive(:moar_chairs) }
    end
  end
end

<强>更新

或者，为了更好的语义，添加一个名为action的spec helper方法，如下所示：

def action(&block)
  shared_context "run action before", run_action: :first do
    before(&block)
  end
  shared_context "run action after", run_action: :last do
    after(&block)
  end
end

然后示例如下：

describe DinnerTable do
  subject(:table) { DinnerTable.new }

  describe "#arrange", run_action: :last do
    action { table.arrange(group) }

    context "when arranging for family" do
      let(:group) { :family }
      specify { table.should_not receive(:moar_chairs) }
    end

    context "when arranging for guests" do
      let(:group) { :guests }
      specify { table.should receive(:moar_chairs) }
    end
  end
end

对于在RSpec中使用接收匹配器的示例，有没有办法设置公共代码块（即每个＆＃39;之前的＃39;）？

2 个答案: