Yockeries - Factories and Mocks from YAML

yaml_objects.rb

# Yockeries - Yaml + Mocks + Factories(easy way to create them)
#
# Long ago there was an uprising against YAML fixtures in the rails world. Some
# people replaced them with things like FactoryGirl, Machinist, Fabrication, and a
# bunch of others.
#
# However, YAML is still the simpliest thing that works, because it comes with
# Ruby. When you load in a yaml file with YAML.load_file, the yaml data is
# converted into a hash, which again is simple to use and test. You can take
# that hash and create a new object with it: Person.new(yaml_converted_hash),
# you can use it to create a stand-in double/mock:
# OpenStruct.new(yaml_converted_hash). 
#
# What I've done with "Yockeries" is to make that a tiny bit simplier with a
# small amount of code.
#
# Yockeries gives a convienent yaml loader (smart enough to know if you are
# using rspec, minitest, or testunit) to load an entire fixture file into a hash
# and then use the +get+ method to select which yaml object you want to work
# with. 
#
# There is also a method +mock_for+ that will create an OpenStruct object where
# you can create a very simple test double/mock. 


# YAML File (people.yaml)
#
# robert:
#   name: Robert Evans
#   email: robert@example.com
#   username: revans
#   password: 123456
#   password_confirmation: 123456




# Examples:
#
# Load a specific User from a YAML File
#
# fixture(:people).get(:robert) # => {:name=>"Robert Evans", :email=>"robert@example.com", :username=>"revans", :password=>123456, :password_confirmation=>123456}
#
#
# Load a mock Object from the YAML file
#
# fixture(:people).mock_for(:robert) # => #<OpenStruct name="Robert Evans", email="robert@example.com", username="revans", password=123456, password_confirmation=123456> 

# Real world example with testunit:
#
# assert_difference "Person.count", 1 do
#   Person.new(
#     fixture(:people).get(:robert)
#   )
# end

# Real world example with rspec
#
# expect {
#   Person.new(
#     fixture(:people).get(:robert)
#   ).save
# }.to change { Person.count }.by(1)

yockeries.rb

require 'yaml'
require 'ostruct'

module Yockeries
  class YockHash < Hash
    def initialize(hash = {})
      @hash = symbolize_keys(hash)
    end

    def get(name)
      @hash[name.to_sym]
    end

    def mock_for(name)
      OpenStruct.new(get(name))
    end

    private

    def symbolize_keys(hash)
      case hash
      when Array
        symbolize_array_keys(hash)
      when Hash
        symbolize_hash_keys(hash)
      else
        hash
      end
    end

    def symbolize_array_keys(array)
      array.inject([]) do |result, value|
        result << case value
        when Hash, Array
          symbolize_keys(value)
        else
          value
        end
        result
      end
    end

    def symbolize_hash_keys(hash)
      hash.inject({}) do |result, (key,value)|
        nval = case value
        when Hash, Array
          symbolize_keys(value)
        else
          value
        end
        result[key.to_sym] = nval
        result
      end
    end

  end


  module Loader
    def fixture(filename)
      dir = File.exists?('test') ? 'test' : 'spec'
      ::Yockeries::YockHash.new(YAML.load_file("#{dir}/fixtures/#{filename.to_s}.yaml"))
    end
  end
end

yockeries_test.rb

require 'minitest/autorun'
require './yockeries'

module Yockeries
  describe YockHash do
    let(:hash) do
      { 'user_1' => { 'name' => 'robert', 'email' => 'robert@example.com' },
        'user_2' => { 'name' => 'tyler',  'email' => 'ty@example.com' } }
    end

    subject { YockHash.new(hash) }

    it 'symbolizes the keys' do
      subject.get('user_1').key?(:name).must_equal true
    end

    it 'will return the name for user_1' do
      subject.get('user_1')[:name].must_equal 'robert'
    end

    it 'will return the name for user_2' do
      subject.get('user_2')[:name].must_equal 'tyler'
    end

    it 'will return a mock' do
      subject.mock_for('user_1').kind_of?(OpenStruct).must_equal true
    end

    it 'mocks will imitate an object' do
      subject.mock_for('user_1').name.must_equal 'robert'
    end
  end
end