activerecord - 为什么在 Rspec 示例中未定义方法 "has_many"？

Question

我正在玩一个关于通过 RSpec 中的关联测试 has_many 的示例。
我得到一个

   1) Foo specifies items       Failure/Error: subject.should have_many(:items)       NoMethodError:         undefined method `has_many?' for #       # ./spec/models/foo_spec.rb:10

My question: Why would has_many be undefined?

The spec is:

describe Foo do
  it "specifies items" do
    subject.should have_many(:items)
  end
end

我的模型是:

foo.rb:

 class Foo < ActiveRecord::Base
   has_many :bars
   has_many :items, :through => :bars
 end

酒吧.rb:

class Bar < ActiveRecord::Base
  belongs_to :foo
  belongs_to :item
end

和 item.rb:

class Item < ActiveRecord::Base
  has_many :foos, :through => :bars
  has_many :bars
end

Answer 1

嗯，没有has_many?模型对象的方法。和 rspec-rails默认情况下不提供此类匹配器。然而，shoulda-matchers gem 做:

describe Post do
  it { should belong_to(:user) }
  it { should have_many(:tags).through(:taggings) }
end

describe User do
  it { should have_many(:posts) }
end

(例如来自 shoulda-matchers documentation )

只需添加 gem 'shoulda-matchers'给您的 Gemfile您将能够使用该语法。