如何将实例变量传递给RSpec共享示例

Question

我正在使用RSpec（2.10.1）在模型上测试验证并提取了一些代码以与其他模型验证共享。该验证首次写在公司的表，所以代码如下所示：

# support/shared_examples.rb 
shared_examples "a text field" do |field, fill, length| 
    it "it should be long enough" do 
    @company.send("#{field}=", fill * length) 
    @company.should be_valid 
    end 

    etc... 
end 

和用法是：

# company_spec.rb 
describe Company do 
    before { @company = Company.new(init stuff here) } 

    describe "when address2" do 
    it_behaves_like "a text field", "address2", "a", Company.address2.limit 
    end 

    etc... 
end 

我想给@company作为参数传递到共享例如，所以我可以重用像这样不同型号代码，东西：

# support/shared_examples.rb 
shared_examples "a text field" do |model, field, fill, length| 
    it "it should be long enough" do 
    model.send("#{field}=", fill * length) 
    model.should be_valid 
    end 

    etc... 
end 

和用法是：

# company_spec.rb 
describe Company do 
    before { @company = Company.new(init stuff here) } 

    describe "when address2" do 
    it_behaves_like "a text field", @company, "address2", "a", Company.address2.limit 
    end 

    etc... 
end 

但是，当我这样做时，我得到undefined method 'address2' for nil:NilClass。看来@company没有被传递（不在范围内？）我如何得到这样的东西来工作？

Answer 1

问题是self示例组中的self与self不同，它在before挂钩中，因此即使它具有相同的名称也不是同一个实例变量。

我建议你使用let对于这样的情况：

# support/shared_examples.rb 
shared_examples "a text field" do |field, fill, length| 
    it "it should be long enough" do 
    model.send("#{field}=", fill * length) 
    model.should be_valid 
    end 
end 

# company_spec.rb 
describe Company do 
    describe "when address2" do 
    it_behaves_like "a text field", "address2", "a", Company.address2.limit do 
     let(:model) { Company.new(init stuff here) } 
    end 
    end 
end