超类不匹配，结构，重新加载和Spork

问题描述：

假设有以下类

# derp.rb
class Derp < Struct.new :id
end

当I load时。 /derp.rb两次程序失败， TypeError：class class Derp 的超类不匹配。好的，这可以用 require 来管理。但是如何使用Spork为每个测试运行重新加载这样的类？ require 显然不会工作，因为它会缓存加载的文件。

When I load "./derp.rb" twice the program fails with TypeError: superclass mismatch for class Derp. Ok, this could be managed with require. But how can I reload such classes for each test run with Spork? require obviously won't work cause it caches the loaded files.

答

Struct.new 正在为您的每个载入创建新类。

Struct.new is creating new class for your every load.

irb(main):001:0> class Test1 < Struct.new :id; end
nil
irb(main):003:0> class Test1 < Struct.new :id; end
TypeError: superclass mismatch for class Test1
    from (irb):3
    from /usr/bin/irb:12:in `<main>'

您可以保存 Struct.new 返回的到一个变量，你
可以使用它总是相同 class 。

You can save your Struct.new returned class to a variable and you can use that will be always the same class.

irb(main):004:0> Id = Struct.new :id
#<Class:0x00000002c35b20>
irb(main):005:0> class Test2 < Id; end
nil
irb(main):006:0> class Test2 < Id; end
nil

或者您可以使用Struct.new 块样式而不是类关键字it 只会给出警告：已经初始化的常量Test3 重新载入您的档案。

or You can use Struct.new block style instead of class keyword it will only give warning: already initialized constant Test3 when you reload your file.

irb(main):023:0> Test3 = Struct.new(:id) do
                     def my_methods
                     "this is a method"
                     end
                   end

超类不匹配，结构，重新加载和Spork

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