rails--rails/activerecord/lib/active_record/fixtures.rb

require 'erb'

begin
  require 'psych'
rescue LoadError
end

require 'yaml'
require 'csv'
require 'zlib'
require 'active_support/dependencies'
require 'active_support/core_ext/array/wrap'
require 'active_support/core_ext/object/blank'
require 'active_support/core_ext/logger'
require 'active_support/ordered_hash'

if defined? ActiveRecord
  class FixtureClassNotFound < ActiveRecord::ActiveRecordError #:nodoc:
  end
else
  class FixtureClassNotFound < StandardError #:nodoc:
  end
end

class FixturesFileNotFound < StandardError; end

# Fixtures are a way of organizing data that you want to test against; in short, sample data.
#
# = Fixture formats
#
# Fixtures come in 3 flavors:
#
#   1.  YAML fixtures
#   2.  CSV fixtures
#   3.  Single-file fixtures
#
# == YAML fixtures
#
# This type of fixture is in YAML format and the preferred default. YAML is a file format which describes data structures
# in a non-verbose, human-readable format. It ships with Ruby 1.8.1+.
#
# Unlike single-file fixtures, YAML fixtures are stored in a single file per model, which are placed
# in the directory appointed by <tt>ActiveSupport::TestCase.fixture_path=(path)</tt> (this is
# automatically configured for Rails, so you can just put your files in <tt><your-rails-app>/test/fixtures/</tt>).
# The fixture file ends with the <tt>.yml</tt> file extension (Rails example:
# <tt><your-rails-app>/test/fixtures/web_sites.yml</tt>). The format of a YAML fixture file looks like this:
#
#   rubyonrails:
#     id: 1
#     name: Ruby on Rails
#     url: http://www.rubyonrails.org
#
#   google:
#     id: 2
#     name: Google
#     url: http://www.google.com
#
# This YAML fixture file includes two fixtures.  Each YAML fixture (ie. record) is given a name and is followed by an
# indented list of key/value pairs in the "key: value" format.  Records are separated by a blank line for your viewing
# pleasure.
#
# Note that YAML fixtures are unordered. If you want ordered fixtures, use the omap YAML type.
# See http://yaml.org/type/omap.html
# for the specification.  You will need ordered fixtures when you have foreign key constraints on keys in the same table.
# This is commonly needed for tree structures.  Example:
#
#    --- !omap
#    - parent:
#        id:         1
#        parent_id:  NULL
#        title:      Parent
#    - child:
#        id:         2
#        parent_id:  1
#        title:      Child
#
# == CSV fixtures
#
# Fixtures can also be kept in the Comma Separated Value (CSV) format. Akin to YAML fixtures, CSV fixtures are stored
# in a single file, but instead end with the <tt>.csv</tt> file extension
# (Rails example: <tt><your-rails-app>/test/fixtures/web_sites.csv</tt>).
#
# The format of this type of fixture file is much more compact than the others, but also a little harder to read by us
# humans.  The first line of the CSV file is a comma-separated list of field names.  The rest of the
# file is then comprised
# of the actual data (1 per line).  Here's an example:
#
#   id, name, url
#   1, Ruby On Rails, http://www.rubyonrails.org
#   2, Google, http://www.google.com
#
# Should you have a piece of data with a comma character in it, you can place double quotes around that value.  If you
# need to use a double quote character, you must escape it with another double quote.
#
# Another unique attribute of the CSV fixture is that it has *no* fixture name like the other two formats.  Instead, the
# fixture names are automatically generated by deriving the class name of the fixture file and adding an incrementing
# number to the end.  In our example, the 1st fixture would be called "web_site_1" and the 2nd one would be called
# "web_site_2".
#
# Most databases and spreadsheets support exporting to CSV format, so this is a great format for you to choose if you
# have existing data somewhere already.
#
# == Single-file fixtures
#
# This type of fixture was the original format for Active Record that has since been deprecated in
# favor of the YAML and CSV formats.
# Fixtures for this format are created by placing text files in a sub-directory (with the name of the model)
# to the directory appointed by <tt>ActiveSupport::TestCase.fixture_path=(path)</tt> (this is automatically
# configured for Rails, so you can just put your files in <tt><your-rails-app>/test/fixtures/<your-model-name>/</tt> --
# like <tt><your-rails-app>/test/fixtures/web_sites/</tt> for the WebSite model).
#
# Each text file placed in this directory represents a "record".  Usually these types of fixtures are named without
# extensions, but if you are on a Windows machine, you might consider adding <tt>.txt</tt> as the extension.
# Here's what the above example might look like:
#
#   web_sites/google
#   web_sites/yahoo.txt
#   web_sites/ruby-on-rails
#
# The file format of a standard fixture is simple.  Each line is a property (or column in db speak) and has the syntax
# of "name => value".  Here's an example of the ruby-on-rails fixture above:
#
#   id => 1
#   name => Ruby on Rails
#   url => http://www.rubyonrails.org
#
# = Using fixtures in testcases
#
# Since fixtures are a testing construct, we use them in our unit and functional tests.  There are two ways to use the
# fixtures, but first let's take a look at a sample unit test:
#
#   require 'test_helper'
#
#   class WebSiteTest < ActiveSupport::TestCase
#     test "web_site_count" do
#       assert_equal 2, WebSite.count
#     end
#   end
#
# By default, the <tt>test_helper module</tt> will load all of your fixtures into your test database,
# so this test will succeed.
# The testing environment will automatically load the all fixtures into the database before each test.
# To ensure consistent data, the environment deletes the fixtures before running the load.
#
# In addition to being available in the database, the fixture's data may also be accessed by
# using a special dynamic method, which has the same name as the model, and accepts the
# name of the fixture to instantiate:
#
#   test "find" do
#     assert_equal "Ruby on Rails", web_sites(:rubyonrails).name
#   end
#
# Alternatively, you may enable auto-instantiation of the fixture data. For instance, take the following tests:
#
#   test "find_alt_method_1" do
#     assert_equal "Ruby on Rails", @web_sites['rubyonrails']['name']
#   end
#
#   test "find_alt_method_2" do
#     assert_equal "Ruby on Rails", @rubyonrails.news
#   end
#
# In order to use these methods to access fixtured data within your testcases, you must specify one of the
# following in your <tt>ActiveSupport::TestCase</tt>-derived class:
#
# - to fully enable instantiated fixtures (enable alternate methods #1 and #2 above)
#     self.use_instantiated_fixtures = true
#
# - create only the hash for the fixtures, do not 'find' each instance (enable alternate method #1 only)
#     self.use_instantiated_fixtures = :no_instances
#
# Using either of these alternate methods incurs a performance hit, as the fixtured data must be fully
# traversed in the database to create the fixture hash and/or instance variables. This is expensive for
# large sets of fixtured data.
#
# = Dynamic fixtures with ERb
#
# Some times you don't care about the content of the fixtures as much as you care about the volume. In these cases, you can
# mix ERb in with your YAML or CSV fixtures to create a bunch of fixtures for load testing, like:
#
#   <% for i in 1..1000 %>
#   fix_<%= i %>:
#     id: <%= i %>
#     name: guy_<%= 1 %>
#   <% end %>
#
# This will create 1000 very simple YAML fixtures.
#
# Using ERb, you can also inject dynamic values into your fixtures with inserts like <tt><%= Date.today.strftime("%Y-%m-%d") %></tt>.
# This is however a feature to be used with some caution. The point of fixtures are that they're
# stable units of predictable sample data. If you feel that you need to inject dynamic values, then
# perhaps you should reexamine whether your application is properly testable. Hence, dynamic values
# in fixtures are to be considered a code smell.
#
# = Transactional fixtures
#
# TestCases can use begin+rollback to isolate their changes to the database instead of having to
# delete+insert for every test case.
#
#   class FooTest < ActiveSupport::TestCase
#     self.use_transactional_fixtures = true
#
#     test "godzilla" do
#       assert !Foo.find(:all).empty?
#       Foo.destroy_all
#       assert Foo.find(:all).empty?
#     end
#
#     test "godzilla aftermath" do
#       assert !Foo.find(:all).empty?
#     end
#   end
#
# If you preload your test database with all fixture data (probably in the Rakefile task) and use transactional fixtures,
# then you may omit all fixtures declarations in your test cases since all the data's already there
# and every case rolls back its changes.
#
# In order to use instantiated fixtures with preloaded data, set +self.pre_loaded_fixtures+ to true. This will provide
# access to fixture data for every table that has been loaded through fixtures (depending on the
# value of +use_instantiated_fixtures+)
#
# When *not* to use transactional fixtures:
#
# 1. You're testing whether a transaction works correctly. Nested transactions don't commit until
#    all parent transactions commit, particularly, the fixtures transaction which is begun in setup
#    and rolled back in teardown. Thus, you won't be able to verify
#    the results of your transaction until Active Record supports nested transactions or savepoints (in progress).
# 2. Your database does not support transactions. Every Active Record database supports transactions except MySQL MyISAM.
#    Use InnoDB, MaxDB, or NDB instead.
#
# = Advanced YAML Fixtures
#
# YAML fixtures that don't specify an ID get some extra features:
#
# * Stable, autogenerated IDs
# * Label references for associations (belongs_to, has_one, has_many)
# * HABTM associations as inline lists
# * Autofilled timestamp columns
# * Fixture label interpolation
# * Support for YAML defaults
#
# == Stable, autogenerated IDs
#
# Here, have a monkey fixture:
#
#   george:
#     id: 1
#     name: George the Monkey
#
#   reginald:
#     id: 2
#     name: Reginald the Pirate
#
# Each of these fixtures has two unique identifiers: one for the database
# and one for the humans. Why don't we generate the primary key instead?
# Hashing each fixture's label yields a consistent ID:
#
#   george: # generated id: 503576764
#     name: George the Monkey
#
#   reginald: # generated id: 324201669
#     name: Reginald the Pirate
#
# Active Record looks at the fixture's model class, discovers the correct
# primary key, and generates it right before inserting the fixture
# into the database.
#
# The generated ID for a given label is constant, so we can discover
# any fixture's ID without loading anything, as long as we know the label.
#
# == Label references for associations (belongs_to, has_one, has_many)
#
# Specifying foreign keys in fixtures can be very fragile, not to
# mention difficult to read. Since Active Record can figure out the ID of
# any fixture from its label, you can specify FK's by label instead of ID.
#
# === belongs_to
#
# Let's break out some more monkeys and pirates.
#
#   ### in pirates.yml
#
#   reginald:
#     id: 1
#     name: Reginald the Pirate
#     monkey_id: 1
#
#   ### in monkeys.yml
#
#   george:
#     id: 1
#     name: George the Monkey
#     pirate_id: 1
#
# Add a few more monkeys and pirates and break this into multiple files,
# and it gets pretty hard to keep track of what's going on. Let's
# use labels instead of IDs:
#
#   ### in pirates.yml
#
#   reginald:
#     name: Reginald the Pirate
#     monkey: george
#
#   ### in monkeys.yml
#
#   george:
#     name: George the Monkey
#     pirate: reginald
#
# Pow! All is made clear. Active Record reflects on the fixture's model class,
# finds all the +belongs_to+ associations, and allows you to specify
# a target *label* for the *association* (monkey: george) rather than
# a target *id* for the *FK* (<tt>monkey_id: 1</tt>).
#
# ==== Polymorphic belongs_to
#
# Supporting polymorphic relationships is a little bit more complicated, since
# Active Record needs to know what type your association is pointing at. Something
# like this should look familiar:
#
#   ### in fruit.rb
#
#   belongs_to :eater, :polymorphic => true
#
#   ### in fruits.yml
#
#   apple:
#     id: 1
#     name: apple
#     eater_id: 1
#     eater_type: Monkey
#
# Can we do better? You bet!
#
#   apple:
#     eater: george (Monkey)
#
# Just provide the polymorphic target type and Active Record will take care of the rest.
#
# === has_and_belongs_to_many
#
# Time to give our monkey some fruit.
#
#   ### in monkeys.yml
#
#   george:
#     id: 1
#     name: George the Monkey
#
#   ### in fruits.yml
#
#   apple:
#     id: 1
#     name: apple
#
#   orange:
#     id: 2
#     name: orange
#
#   grape:
#     id: 3
#     name: grape
#
#   ### in fruits_monkeys.yml
#
#   apple_george:
#     fruit_id: 1
#     monkey_id: 1
#
#   orange_george:
#     fruit_id: 2
#     monkey_id: 1
#
#   grape_george:
#     fruit_id: 3
#     monkey_id: 1
#
# Let's make the HABTM fixture go away.
#
#   ### in monkeys.yml
#
#   george:
#     id: 1
#     name: George the Monkey
#     fruits: apple, orange, grape
#
#   ### in fruits.yml
#
#   apple:
#     name: apple
#
#   orange:
#     name: orange
#
#   grape:
#     name: grape
#
# Zap! No more fruits_monkeys.yml file. We've specified the list of fruits
# on George's fixture, but we could've just as easily specified a list
# of monkeys on each fruit. As with +belongs_to+, Active Record reflects on
# the fixture's model class and discovers the +has_and_belongs_to_many+
# associations.
#
# == Autofilled timestamp columns
#
# If your table/model specifies any of Active Record's
# standard timestamp columns (+created_at+, +created_on+, +updated_at+, +updated_on+),
# they will automatically be set to <tt>Time.now</tt>.
#
# If you've set specific values, they'll be left alone.
#
# == Fixture label interpolation
#
# The label of the current fixture is always available as a column value:
#
#   geeksomnia:
#     name: Geeksomnia's Account
#     subdomain: $LABEL
#
# Also, sometimes (like when porting older join table fixtures) you'll need
# to be able to get a hold of the identifier for a given label. ERB
# to the rescue:
#
#   george_reginald:
#     monkey_id: <%= Fixtures.identify(:reginald) %>
#     pirate_id: <%= Fixtures.identify(:george) %>
#
# == Support for YAML defaults
#
# You probably already know how to use YAML to set and reuse defaults in
# your <tt>database.yml</tt> file. You can use the same technique in your fixtures:
#
#   DEFAULTS: &DEFAULTS
#     created_on: <%= 3.weeks.ago.to_s(:db) %>
#
#   first:
#     name: Smurf
#     <<: *DEFAULTS
#
#   second:
#     name: Fraggle
#     <<: *DEFAULTS
#
# Any fixture labeled "DEFAULTS" is safely ignored.

class Fixtures
  MAX_ID = 2 ** 30 - 1

  @@all_cached_fixtures = Hash.new { |h,k| h[k] = {} }

  def self.find_table_name(table_name) # :nodoc:
    ActiveRecord::Base.pluralize_table_names ?
      table_name.to_s.singularize.camelize :
      table_name.to_s.camelize
  end

  def self.reset_cache
    @@all_cached_fixtures.clear
  end

  def self.cache_for_connection(connection)
    @@all_cached_fixtures[connection]
  end

  def self.fixture_is_cached?(connection, table_name)
    cache_for_connection(connection)[table_name]
  end

  def self.cached_fixtures(connection, keys_to_fetch = nil)
    if keys_to_fetch
      cache_for_connection(connection).values_at(*keys_to_fetch)
    else
      cache_for_connection(connection).values
    end
  end

  def self.cache_fixtures(connection, fixtures_map)
    cache_for_connection(connection).update(fixtures_map)
  end

  def self.instantiate_fixtures(object, table_name, fixtures, load_instances = true)
    object.instance_variable_set "@#{table_name.to_s.gsub('.','_')}", fixtures
    if load_instances
      fixtures.each do |name, fixture|
        begin
          object.instance_variable_set "@#{name}", fixture.find
        rescue FixtureClassNotFound
          nil
        end
      end
    end
  end

  def self.instantiate_all_loaded_fixtures(object, load_instances = true)
    all_loaded_fixtures.each do |table_name, fixtures|
      Fixtures.instantiate_fixtures(object, table_name, fixtures, load_instances)
    end
  end

  cattr_accessor :all_loaded_fixtures
  self.all_loaded_fixtures = {}

  def self.create_fixtures(fixtures_directory, table_names, class_names = {})
    table_names = [table_names].flatten.map { |n| n.to_s }
    table_names.each { |n|
      class_names[n.tr('/', '_').to_sym] = n.classify if n.include?('/')
    }

    # FIXME: Apparently JK uses this.
    connection = block_given? ? yield : ActiveRecord::Base.connection

    files_to_read = table_names.reject { |table_name| fixture_is_cached?(connection, table_name) }

    unless files_to_read.empty?
      connection.disable_referential_integrity do
        fixtures_map = {}

        fixture_files = files_to_read.map do |path|
          table_name = path.tr '/', '_'

          fixtures_map[path] = Fixtures.new(
            connection,
            table_name,
            class_names[table_name.to_sym],
            File.join(fixtures_directory, path))
        end

        all_loaded_fixtures.update(fixtures_map)

        connection.transaction(:requires_new => true) do
          fixture_files.each do |ff|
            conn = ff.model_class.respond_to?(:connection) ? ff.model_class.connection : connection
            table_rows = ff.table_rows

            table_rows.keys.each do |table|
              conn.delete "DELETE FROM #{conn.quote_table_name(table)}", 'Fixture Delete'
            end

            table_rows.each do |table_name,rows|
              rows.each do |row|
                conn.insert_fixture(row, table_name)
              end
            end
          end

          # Cap primary key sequences to max(pk).
          if connection.respond_to?(:reset_pk_sequence!)
            table_names.each do |table_name|
              connection.reset_pk_sequence!(table_name.tr('/', '_'))
            end
          end
        end

        cache_fixtures(connection, fixtures_map)
      end
    end
    cached_fixtures(connection, table_names)
  end

  # Returns a consistent, platform-independent identifier for +label+.
  # Identifiers are positive integers less than 2^32.
  def self.identify(label)
    Zlib.crc32(label.to_s) % MAX_ID
  end

  attr_reader :table_name, :name, :fixtures, :model_class

  def initialize(connection, table_name, class_name, fixture_path)
    @connection   = connection
    @table_name   = table_name
    @fixture_path = fixture_path
    @name         = table_name # preserve fixture base name
    @class_name   = class_name

    @fixtures     = ActiveSupport::OrderedHash.new
    @table_name   = "#{ActiveRecord::Base.table_name_prefix}#{@table_name}#{ActiveRecord::Base.table_name_suffix}"

    # Should be an AR::Base type class
    if class_name.is_a?(Class)
      @table_name   = class_name.table_name
      @connection   = class_name.connection
      @model_class  = class_name
    else
      @model_class  = class_name.constantize rescue nil
    end

    read_fixture_files
  end

  def [](x)
    fixtures[x]
  end

  def []=(k,v)
    fixtures[k] = v
  end

  def each(&block)
    fixtures.each(&block)
  end

  def size
    fixtures.size
  end

  # Return a hash of rows to be inserted.  The key is the table, the value is
  # a list of rows to insert to that table.
  def table_rows
    now = ActiveRecord::Base.default_timezone == :utc ? Time.now.utc : Time.now
    now = now.to_s(:db)

    # allow a standard key to be used for doing defaults in YAML
    fixtures.delete('DEFAULTS')

    # track any join tables we need to insert later
    rows = Hash.new { |h,table| h[table] = [] }

    rows[table_name] = fixtures.map do |label, fixture|
      row = fixture.to_hash

      if model_class && model_class < ActiveRecord::Base
        # fill in timestamp columns if they aren't specified and the model is set to record_timestamps
        if model_class.record_timestamps
          timestamp_column_names.each do |name|
            row[name] = now unless row.key?(name)
          end
        end

        # interpolate the fixture label
        row.each do |key, value|
          row[key] = label if value == "$LABEL"
        end

        # generate a primary key if necessary
        if has_primary_key_column? && !row.include?(primary_key_name)
          row[primary_key_name] = Fixtures.identify(label)
        end

        # If STI is used, find the correct subclass for association reflection
        reflection_class =
          if row.include?(inheritance_column_name)
            row[inheritance_column_name].constantize rescue model_class
          else
            model_class
          end

        reflection_class.reflect_on_all_associations.each do |association|
          case association.macro
          when :belongs_to
            # Do not replace association name with association foreign key if they are named the same
            fk_name = (association.options[:foreign_key] || "#{association.name}_id").to_s

            if association.name.to_s != fk_name && value = row.delete(association.name.to_s)
              if association.options[:polymorphic] && value.sub!(/\s*\(([^\)]*)\)\s*$/, "")
                # support polymorphic belongs_to as "label (Type)"
                row[association.foreign_type] = $1
              end

              row[fk_name] = Fixtures.identify(value)
            end
          when :has_and_belongs_to_many
            if (targets = row.delete(association.name.to_s))
              targets = targets.is_a?(Array) ? targets : targets.split(/\s*,\s*/)
              table_name = association.options[:join_table]
              rows[table_name].concat targets.map { |target|
                { association.foreign_key             => row[primary_key_name],
                  association.association_foreign_key => Fixtures.identify(target) }
              }
            end
          end
        end
      end

      row
    end
    rows
  end

  private
    def primary_key_name
      @primary_key_name ||= model_class && model_class.primary_key
    end

    def has_primary_key_column?
      @has_primary_key_column ||= primary_key_name &&
        model_class.columns.any? { |c| c.name == primary_key_name }
    end

    def timestamp_column_names
      @timestamp_column_names ||=
        %w(created_at created_on updated_at updated_on) & column_names
    end

    def inheritance_column_name
      @inheritance_column_name ||= model_class && model_class.inheritance_column
    end

    def column_names
      @column_names ||= @connection.columns(@table_name).collect { |c| c.name }
    end

    def read_fixture_files
      if File.file?(yaml_file_path)
        read_yaml_fixture_files
      elsif File.file?(csv_file_path)
        read_csv_fixture_files
      else
        raise FixturesFileNotFound, "Could not find #{yaml_file_path} or #{csv_file_path}"
      end
    end

    def read_yaml_fixture_files
      yaml_string = (Dir["#{@fixture_path}/**/*.yml"].select { |f|
        File.file?(f)
      } + [yaml_file_path]).map { |file_path| IO.read(file_path) }.join

      if yaml = parse_yaml_string(yaml_string)
        # If the file is an ordered map, extract its children.
        yaml_value =
          if yaml.respond_to?(:type_id) && yaml.respond_to?(:value)
            yaml.value
          else
            [yaml]
          end

        yaml_value.each do |fixture|
          raise Fixture::FormatError, "Bad data for #{@class_name} fixture named #{fixture}" unless fixture.respond_to?(:each)
          fixture.each do |name, data|
            unless data
              raise Fixture::FormatError, "Bad data for #{@class_name} fixture named #{name} (nil)"
            end

            fixtures[name] = Fixture.new(data, model_class)
          end
        end
      end
    end

    def read_csv_fixture_files
      reader = CSV.parse(erb_render(IO.read(csv_file_path)))
      header = reader.shift
      i = 0
      reader.each do |row|
        data = {}
        row.each_with_index { |cell, j| data[header[j].to_s.strip] = cell.to_s.strip }
        fixtures["#{@class_name.to_s.underscore}_#{i+=1}"] = Fixture.new(data, model_class)
      end
    end

    def yaml_file_path
      "#{@fixture_path}.yml"
    end

    def csv_file_path
      @fixture_path + ".csv"
    end

    def yaml_fixtures_key(path)
      File.basename(@fixture_path).split(".").first
    end

    def parse_yaml_string(fixture_content)
      YAML::load(erb_render(fixture_content))
    rescue => error
      raise Fixture::FormatError, "a YAML error occurred parsing #{yaml_file_path}. Please note that YAML must be consistently indented using spaces. Tabs are not allowed. Please have a look at http://www.yaml.org/faq.html\nThe exact error was:\n  #{error.class}: #{error}"
    end

    def erb_render(fixture_content)
      ERB.new(fixture_content).result
    end
end

class Fixture #:nodoc:
  include Enumerable

  class FixtureError < StandardError #:nodoc:
  end

  class FormatError < FixtureError #:nodoc:
  end

  attr_reader :model_class, :fixture

  def initialize(fixture, model_class)
    @fixture     = fixture
    @model_class = model_class
  end

  def class_name
    model_class.name if model_class
  end

  def each
    fixture.each { |item| yield item }
  end

  def [](key)
    fixture[key]
  end

  alias :to_hash :fixture

  def find
    if model_class
      model_class.find(fixture[model_class.primary_key])
    else
      raise FixtureClassNotFound, "No class attached to find."
    end
  end
end

module ActiveRecord
  module TestFixtures
    extend ActiveSupport::Concern

    included do
      setup :setup_fixtures
      teardown :teardown_fixtures

      class_attribute :fixture_path
      class_attribute :fixture_table_names
      class_attribute :fixture_class_names
      class_attribute :use_transactional_fixtures
      class_attribute :use_instantiated_fixtures   # true, false, or :no_instances
      class_attribute :pre_loaded_fixtures

      self.fixture_table_names = []
      self.use_transactional_fixtures = true
      self.use_instantiated_fixtures = false
      self.pre_loaded_fixtures = false

      self.fixture_class_names = Hash.new do |h, table_name|
        h[table_name] = Fixtures.find_table_name(table_name)
      end
    end

    module ClassMethods
      def set_fixture_class(class_names = {})
        self.fixture_class_names = self.fixture_class_names.merge(class_names)
      end

      def fixtures(*table_names)
        if table_names.first == :all
          table_names = Dir["#{fixture_path}/**/*.{yml,csv}"]
          table_names.map! { |f| f[(fixture_path.size + 1)..-5] }
        else
          table_names = table_names.flatten.map { |n| n.to_s }
        end

        self.fixture_table_names |= table_names
        require_fixture_classes(table_names)
        setup_fixture_accessors(table_names)
      end

      def try_to_load_dependency(file_name)
        require_dependency file_name
      rescue LoadError => e
        # Let's hope the developer has included it himself

        # Let's warn in case this is a subdependency, otherwise
        # subdependency error messages are totally cryptic
        if ActiveRecord::Base.logger
          ActiveRecord::Base.logger.warn("Unable to load #{file_name}, underlying cause #{e.message} \n\n #{e.backtrace.join("\n")}")
        end
      end

      def require_fixture_classes(table_names = nil)
        (table_names || fixture_table_names).each do |table_name|
          file_name = table_name.to_s
          file_name = file_name.singularize if ActiveRecord::Base.pluralize_table_names
          try_to_load_dependency(file_name)
        end
      end

      def setup_fixture_accessors(table_names = nil)
        table_names = Array.wrap(table_names || fixture_table_names)
        table_names.each do |table_name|
          table_name = table_name.to_s.tr('./', '_')

          redefine_method(table_name) do |*fixtures|
            force_reload = fixtures.pop if fixtures.last == true || fixtures.last == :reload

            @fixture_cache[table_name] ||= {}

            instances = fixtures.map do |fixture|
              @fixture_cache[table_name].delete(fixture) if force_reload

              if @loaded_fixtures[table_name][fixture.to_s]
                @fixture_cache[table_name][fixture] ||= @loaded_fixtures[table_name][fixture.to_s].find
              else
                raise StandardError, "No fixture with name '#{fixture}' found for table '#{table_name}'"
              end
            end

            instances.size == 1 ? instances.first : instances
          end
          private table_name
        end
      end

      def uses_transaction(*methods)
        @uses_transaction = [] unless defined?(@uses_transaction)
        @uses_transaction.concat methods.map { |m| m.to_s }
      end

      def uses_transaction?(method)
        @uses_transaction = [] unless defined?(@uses_transaction)
        @uses_transaction.include?(method.to_s)
      end
    end

    def run_in_transaction?
      use_transactional_fixtures &&
        !self.class.uses_transaction?(method_name)
    end

    def setup_fixtures
      return unless defined?(ActiveRecord) && !ActiveRecord::Base.configurations.blank?

      if pre_loaded_fixtures && !use_transactional_fixtures
        raise RuntimeError, 'pre_loaded_fixtures requires use_transactional_fixtures'
      end

      @fixture_cache = {}
      @@already_loaded_fixtures ||= {}

      # Load fixtures once and begin transaction.
      if run_in_transaction?
        if @@already_loaded_fixtures[self.class]
          @loaded_fixtures = @@already_loaded_fixtures[self.class]
        else
          @loaded_fixtures = load_fixtures
          @@already_loaded_fixtures[self.class] = @loaded_fixtures
        end
        ActiveRecord::Base.connection.increment_open_transactions
        ActiveRecord::Base.connection.transaction_joinable = false
        ActiveRecord::Base.connection.begin_db_transaction
      # Load fixtures for every test.
      else
        Fixtures.reset_cache
        @@already_loaded_fixtures[self.class] = nil
        @loaded_fixtures = load_fixtures
      end

      # Instantiate fixtures for every test if requested.
      instantiate_fixtures if use_instantiated_fixtures
    end

    def teardown_fixtures
      return unless defined?(ActiveRecord) && !ActiveRecord::Base.configurations.blank?

      unless run_in_transaction?
        Fixtures.reset_cache
      end

      # Rollback changes if a transaction is active.
      if run_in_transaction? && ActiveRecord::Base.connection.open_transactions != 0
        ActiveRecord::Base.connection.rollback_db_transaction
        ActiveRecord::Base.connection.decrement_open_transactions
      end
      ActiveRecord::Base.clear_active_connections!
    end

    private
      def load_fixtures
        fixtures = Fixtures.create_fixtures(fixture_path, fixture_table_names, fixture_class_names)
        Hash[fixtures.map { |f| [f.name, f] }]
      end

      # for pre_loaded_fixtures, only require the classes once. huge speed improvement
      @@required_fixture_classes = false

      def instantiate_fixtures
        if pre_loaded_fixtures
          raise RuntimeError, 'Load fixtures before instantiating them.' if Fixtures.all_loaded_fixtures.empty?
          unless @@required_fixture_classes
            self.class.require_fixture_classes Fixtures.all_loaded_fixtures.keys
            @@required_fixture_classes = true
          end
          Fixtures.instantiate_all_loaded_fixtures(self, load_instances?)
        else
          raise RuntimeError, 'Load fixtures before instantiating them.' if @loaded_fixtures.nil?
          @loaded_fixtures.each do |table_name, fixtures|
            Fixtures.instantiate_fixtures(self, table_name, fixtures, load_instances?)
          end
        end
      end

      def load_instances?
        use_instantiated_fixtures != :no_instances
      end
  end
end