Question

在一堆rspec rails单元规范中，我做了类似的事情：

describe Foo do
  [:bar, :baz].each do |a|
    it "should have many #{a}" do
      Foo.should have_many(a)
    end
  end
end

对于更干净的代码，我宁愿做类似的事情：

describe Foo do
  spec_has_many Foo, :bar, :baz
end

那么如何编写像spec_has_many()这样的辅助方法来插入像rspec的it()方法这样的DSL代码呢？如果它是一个普通的实例方法，我会做类似的事情：

def spec_has_many(model, *args)
  args.each do |a|
    define_method("it_should_have_many_#{a}") do
      model.should have_many(a)
    end
  end
end

定义rspec示例的等价物是什么？

Answer 1

好的，这需要一些麻烦，但我认为我得到了它的工作。这是一个元编程的hackery，我个人只会使用你描述的第一件事，但这就是你想要的：P

module ExampleMacros
  def self.included(base)
    base.extend(ClassMethods)
  end

  module ClassMethods
    # This will be available as a "Class Macro" in the included class
    def should_have_many(*args)
      args.each do |a|
        # Runs the 'it' block in the context of the current instance
        instance_eval do
          # This is just normal RSpec code at this point
          it "should have_many #{a.to_s}" do
            subject.should have_many(a)
          end
        end
      end
    end
  end
end

describe Foo do
  # Include the module which will define the should_have_many method
  # Can be done automatically in RSpec configuration (see below)
  include ExampleMacros

  # This may or may not be required, but the should_have_many method expects
  # subject to be defined (which it is by default, but this just makes sure
  # it's what we expect)
  subject { Foo }

  # And off we go. Note that you don't need to pass it a model
  should_have_many :a, :b
end

我的规格失败，因为Foo没有has_many?方法，但两个测试都运行，所以它应该可以工作。

您可以在spec_helper.rb文件中定义（并重命名）ExampleMacros模块，它可以包含在内。您想在include ExampleMacros区块中调用describe（而不是其他任何区块）。

要使所有规范自动包含模块，请按以下方式配置RSpec：

# RSpec 2.0.0
RSpec.configure do |c|
  c.include ExampleMacros
end

如何编写插入rspec示例的方法？

1 个答案: