创建简单的自定义 rpec 匹配器时出错

Question

总结我为一个名为 "one_plus" 的方法创建了 rspec 规范，该方法将任何数字加一。我想制作一个匹配器来检查数字是否等于二。

来源 http://www.reactive.io/tips/2008/12/10/up-and-running-with-custom-rspec-matchers/

错误

john@ubuntu:~/Code/Rspec/Misc/CustomRspecMatchers$ rspec one_plus_spec.rb
F

Failures:

  1) the one_plus method should add one to a number
     Failure/Error: one_plus(1).should be_two
     NoMethodError:
       undefined method `two?' for 2:Fixnum
     # ./one_plus_spec.rb:10:in `block (2 levels) in <top (required)>'

Finished in 0.00382 seconds
1 example, 1 failure

Failed examples:

rspec ./one_plus_spec.rb:8 # the one_plus method should add one to a number
john@ubuntu:~/Code/Rspec/Misc/CustomRspecMatchers$

Ruby 宝石 Ruby 2.0.0, Rspec 2.14.1

项目

.
├── matchers.rb
├── one_plus.rb
└── one_plus_spec.rb

one_plus_spec.rb

require 'rubygems'
require 'spec'
require_relative 'one_plus'
require_relative 'matchers'

describe 'the one_plus method' do
  it 'should add one to a number' do
    #one_plus(1).should == 2
    one_plus(1).should be_two

    #one_plus(0).should_not == 2
    one_plus(0).should_not be_two       

  end
end

one_plus.rb

def one_plus(number)
  1 + number
end

matchers.rb

module Matchers
  class BeTwo
    def matches?(actual)
      @actual = actual
      @actual == 2
    end

    def failure_message
      "expected 2 but got '#{@actual}'"
    end

    def negative_failure_message
      "expected something else then 2 but got '#{@actual}'"
    end
  end

  def be_two
    BeTwo.new
  end

  alias :equal_two :be_two

end

****编辑 - Rspec 带回溯的命令****

 # /home/john/.rvm/gems/ruby-2.0.0-p598/gems/rspec-expectations-2.5.0/lib/rspec/matchers/be.rb:130:in matches?'
 # /home/john/.rvm/gems/ruby-2.0.0-p598/gems/rspec-expectations-2.5.0/lib/rspec/expectations/handler.rb:11:in handle_matcher'
 # /home/john/.rvm/gems/ruby-2.0.0-p598/gems/rspec-expectations-2.5.0/lib/rspec/expectations/extensions/kernel.rb:27:in should'
 # ./one_plus_spec.rb:10:in block (2 levels) in <top (required)>'
 # /home/john/.rvm/gems/ruby-2.0.0-p598/gems/rspec-core-2.5.2/lib/rspec/core/example.rb:49:in instance_eval'
 # /home/john/.rvm/gems/ruby-2.0.0-p598/gems/rspec-core-2.5.2/lib/rspec/core/example.rb:49:in block (2 levels) in run'
 # /home/john/.rvm/gems/ruby-2.0.0-p598/gems/rspec-core-2.5.2/lib/rspec/core/example.rb:106:in with_around_hooks'
 # /home/john/.rvm/gems/ruby-2.0.0-p598/gems/rspec-core-2.5.2/lib/rspec/core/example.rb:46:in block in run'
 # /home/john/.rvm/gems/ruby-2.0.0-p598/gems/rspec-core-2.5.2/lib/rspec/core/example.rb:99:in block in with_pending_capture'
 # /home/john/.rvm/gems/ruby-2.0.0-p598/gems/rspec-core-2.5.2/lib/rspec/core/example.rb:98:in catch'
 # /home/john/.rvm/gems/ruby-2.0.0-p598/gems/rspec-core-2.5.2/lib/rspec/core/example.rb:98:in with_pending_capture'
 # /home/john/.rvm/gems/ruby-2.0.0-p598/gems/rspec-core-2.5.2/lib/rspec/core/example.rb:45:in run'
 # /home/john/.rvm/gems/ruby-2.0.0-p598/gems/rspec-core-2.5.2/lib/rspec/core/example_group.rb:262:in block in run_examples'
 # /home/john/.rvm/gems/ruby-2.0.0-p598/gems/rspec-core-2.5.2/lib/rspec/core/example_group.rb:258:in map'
 # /home/john/.rvm/gems/ruby-2.0.0-p598/gems/rspec-core-2.5.2/lib/rspec/core/example_group.rb:258:in run_examples'
 # /home/john/.rvm/gems/ruby-2.0.0-p598/gems/rspec-core-2.5.2/lib/rspec/core/example_group.rb:232:in run'
 # /home/john/.rvm/gems/ruby-2.0.0-p598/gems/rspec-core-2.5.2/lib/rspec/core/command_line.rb:27:in block (2 levels) in run'
 # /home/john/.rvm/gems/ruby-2.0.0-p598/gems/rspec-core-2.5.2/lib/rspec/core/command_line.rb:27:in map'
 # /home/john/.rvm/gems/ruby-2.0.0-p598/gems/rspec-core-2.5.2/lib/rspec/core/command_line.rb:27:in block in run'
 # /home/john/.rvm/gems/ruby-2.0.0-p598/gems/rspec-core-2.5.2/lib/rspec/core/reporter.rb:12:in report'
 # /home/john/.rvm/gems/ruby-2.0.0-p598/gems/rspec-core-2.5.2/lib/rspec/core/command_line.rb:24:in run'
 # /home/john/.rvm/gems/ruby-2.0.0-p598/gems/rspec-core-2.5.2/lib/rspec/core/runner.rb:55:in run_in_process'
 # /home/john/.rvm/gems/ruby-2.0.0-p598/gems/rspec-core-2.5.2/lib/rspec/core/runner.rb:46:in run'
 # /home/john/.rvm/gems/ruby-2.0.0-p598/gems/rspec-core-2.5.2/lib/rspec/core/runner.rb:10:in block in autorun'

Answer 1

RSpec 语法启用此：

require 'rspec/expectations'

RSpec::Matchers.define :be_two do
  match do |actual|
    actual == 2
  end
end

据我所知，此语法适用于 RSpec 2.4 到 3.1，可能还有更多版本。

创建简单的自定义 rpec 匹配器时出错

Error in creating a simple custom rpec matcher

ruby

rspec