ruby - 类型错误 : wrong argument type String (expected Module) when trying to use rspec

Question

检查字符串中子字符串的包含情况。

我认为我使用的是记录在案的正确语法 here ，但这对我不起作用。我错过了什么？

>> require 'rspec-expectations'
=> true
>> s = 'potato'
=> "potato"
>> s.include?('tat')
=> true
>> s.should include('tat')
TypeError: wrong argument type String (expected Module)
    from (irb):4:in `include'
    from (irb):4
    from /usr/bin/irb:12:in `<main>'

Answer 1

应该期望一个匹配器对象，所以回答您问题的最简单方法是:

>> require 'rspec-expectations'
=> true
>> s = 'potato'
=> "potato"
>> s.should RSpec::Matchers::BuiltIn::Include.new('tat')
=> true

让我们暂时谈谈不同的匹配器eq(因为有关于include的东西)

>> require 'rspec-expectations'
=> true
>> s = 'potato'
=> "potato"
>> s.should eq('potato')
NoMethodError: undefined method `eq' for main:Object

为了让eq 起作用，我们可以包含RSpec::Matchers模块(方法定义从第 193 行开始)

>> require 'rspec-expectations'
=> true
>> s = 'potato'
=> "potato"
>> include RSpec::Matchers
>> s.should eq('potato')
=> true

因此，您缺少的是使用 RSpec::Matchers 模块方法扩展您的对象，或者只是将匹配器传递给 should 方法。

IRB 中 include 匹配器的问题仍然存在(不是 100% 确定原因):

>> require 'rspec-expectations'
=> true
>> s = 'potato'
=> "potato"
>> include RSpec::Matchers
>> s.should include('tat')
TypeError: wrong argument type String (expected Module)

这可能与在主对象的上下文中工作有关:

>> self
=> main
>> self.class
=> Object
>> Object.respond_to(:include)
=> false
>> Object.respond_to(:include, true) #check private and protected methods as well
=> true

对象有一个私有(private)方法include。来自 RSpec::Matchers 的包含方法永远不会有机会被调用。如果你将它包装在一个包含 RSpec::Matchers 的类中，一切都应该有效。

Rspec 用 MiniTest::Unit::TestCase 做 RSpec::Matchers (第 168 行)