Rubyonrails RSpec：期望更改多个

在功能规范中提交表单时，我想判断模型中的许多更改.例如，我想确保用户名从X更改为Y，并且加密密码更改了任何值.

我知道已经有一些问题了，但我没有找到适合我的答案.最准确的答案似乎是迈克尔·约翰斯顿的ChangeMultiple matcher:Is it possible for RSpec to expect change in two tables?.它的缺点是只判断从已知值到已知值的显式更改.

我创建了一些伪代码，说明我认为更好的匹配器应该是什么样子:

expect {
  click_button 'Save'
}.to change_multiple { @user.reload }.with_expectations(
  name:               {from: 'donald', to: 'gustav'},
  updated_at:         {by: 4},
  great_field:        {by_at_leaset: 23},
  encrypted_password: true,  # Must change
  created_at:         false, # Must not change
  some_other_field:   nil    # Doesn't matter, but want to denote here that this field exists
)

我还创建了ChangeMultiple matcher的基本框架，如下所示:

module RSpec
  module Matchers
    def change_multiple(receiver=nil, message=nil, &block)
      BuiltIn::ChangeMultiple.new(receiver, message, &block)
    end

    module BuiltIn
      class ChangeMultiple < Change
        def with_expectations(expectations)
          # What to do here? How do I add the expectations passed as argument?
        end
      end
    end
  end
end

但现在我已经发现了这个错误:

 Failure/Error: expect {
   You must pass an argument rather than a block to use the provided matcher (nil), or the matcher must implement `supports_block_expectations?`.
 # ./spec/features/user/registration/edit_spec.rb:20:in `block (2 levels) in <top (required)>'
 # /Users/josh/.rvm/gems/ruby-2.1.0@base/gems/activesupport-4.2.0/lib/active_support/dependencies.rb:268:in `load'
 # /Users/josh/.rvm/gems/ruby-2.1.0@base/gems/activesupport-4.2.0/lib/active_support/dependencies.rb:268:in `block in load'

非常感谢您对创建此定制匹配器的任何帮助.