如何將實例變量傳遞給RSpec共享示例

Question

我正在使用RSpec（2.10.1）在模型上測試驗證並提取了一些代碼以與其他模型驗證共享。該驗證首次寫在公司的表，所以代碼如下所示：

# 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 

我想給@company作爲參數傳遞到共享例如，所以我可以重用像這樣不同型號代碼，東西：

# 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，當我這樣做時，我得到undefined method 'address2' for nil:NilClass。看來@company沒有被傳遞（不在範圍內？）我如何得到這樣的東西來工作？

Answer 1

問題是self示例組中的self與self不同，它在before掛鉤中，因此即使它具有相同的名稱也不是同一個實例變量。

我建議你使用let對於這樣的情況：

# 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