如何测试ruby的初始化方法，该方法又调用私有方法

Question

# frozen_string_literal: true

require 'yaml'
require 'singleton'
require 'pry'

module Plugin
  module Rules
    class RulesLoader
      include Singleton

      attr_reader :definitions

      def initialize
        @definitions = load #it is calling the private method and loads the definitions
      end

      def fetch_rule_definition_for(key)
        definitions[key]
      end

      private
      def load
        #Other code
        Hash = {}
        #this method returns the hash after processing
      end
    end
  end
end

如何为这个类编写规范，其中初始化方法调用私有方法并加载实例变量。由于加载方法是私有的，我不直接调用。

Answer 1

我建议用记忆重写一下。

module Plugin
  module Rules
    class RulesLoader
      include Singleton

      def fetch_rule_definition_for(key)
        @definitions ||= load_definitions
        @definitions[key]
      end

      private

      def load_definitions
        #Other code
        hash = {}
        #this method returns the hash after processing
      end
    end
  end
end

假设的规格：

describe Plugin::Rules::RulesLoader do
  context '#fetch_rule_definition_for' do
    subject(:fetch_rule_definition) { described_class.instance.fetch_rule_definition_for(key) }

    context 'with valid key' do
      let(:key) { :valid_key }

      it 'returns definitions' do
        expect(fetch_rule_definition).to eq(#YOUR_VALUE_HERE#)
      end
    end

    context 'with invalid key' do
      let(:key) { :invalid_key }

      it 'returns nil' do
        expect(fetch_rule_definition).to be_nil
      end
    end
  end
end