Question

规范的相关片段如下：

let(:one_place) { create(:place) }
let(:other_place) { create(:place) }
let(:data) { "saved data" }

shared_examples "saves data to right place" do |right_place|
  it { expect(right_place.data).to eq data }
end

context "when something it saves to one place" do
  it_behaves_like "saves data to right place", one_place
end

context "when whatever it saves to other place" do  
  it_behaves_like "saves data to right place", other_place
end

它可以与常量参数完美配合，但在这种情况下，我收到一个错误：

one_place在示例组（例如describe或context块）上不可用。它仅适用于个别示例（例如it块）或来自示例范围内的构造（例如before，let等）。

如何在这种情况下将延迟创建的变量传递给共享示例？

Answer 1

从docs开始，我认为您需要将let语句放在传递给it_behaves_like的块中：

let(:data) { "saved data" }

shared_examples "saves data to right place" do
  it { expect(right_place.data).to eq data }
end

context "when something it saves to one place" do
  it_behaves_like "saves data to right place" do
    let(:right_place) { create(:place) }
  end
end

context "when whatever it saves to other place" do  
  it_behaves_like "saves data to right place" do
    let(:right_place) { create(:place) }
  end
end

Answer 2

如何在这种情况下将延迟创建的变量传递给共享示例？

好旧记忆有什么不妥？

def one_place
  @one_place ||= create(:place)
end

Answer 3

您也可以使用以下let变量：

shared_examples 'saves data to right place' do

  it { expect(right_place.data).to eq data }

end

context 'when something it saves to one place' do

  let(:right_place) { create(:place) }

  it_behaves_like 'saves data to right place'

end

context 'when whatever it saves to other place' do

  let(:right_place) { create(:place) }

  it_behaves_like 'saves data to right place'

end

注意：仅在插值时使用双引号。

您可以将您的规格干燥如下：

%w(one other).each do |location|

  let(:right_place) { location == one ? create(:place) : create(:place, :other) }

  context "when it saves to #{location} place" do

    it_behaves_like 'saves data to right place'

  end

end

Answer 4

我指出，遗憾的是，你不可能实现的目标。这是可取的，因为它使得这些变量的使用是显式的。上面提到的解决方法（定义让你使用it_behaves_like的位置）有效，但我发现这样写的共享示例令人困惑。

我使用共享示例在共享示例中明确显示所需变量：

RSpec.shared_examples "requires variables" do |variable_names|
  it "(shared example requires `#{variable_names}` to be set)" do
    variable_names = variable_names.kind_of?(Array) ? variable_names : [variable_names]
    temp_config = RSpec::Expectations.configuration.on_potential_false_positives
    RSpec::Expectations.configuration.on_potential_false_positives = :nothing

    variable_names.each do |variable_name|
      expect { send(variable_name) }.to_not raise_error(NameError)
    end

    RSpec::Expectations.configuration.on_potential_false_positives = temp_config
  end
end

像这样使用：

RSpec.shared_examples "saves data to right place" do
  include_examples "requires variables", :right_place

  # ...
end

context "..." do
  let(:right_place) { "" }
  it_behaves_like "saves data to right place"
end

RSpec：如何将“let”变量作为参数传递给共享示例

4 个答案: