active_record_spec.rb

require 'spec_helper'
require 'ostruct'

def save_without_validation(record)
  if ActiveRecord::VERSION::MAJOR < 3
    record.save(false)
  else
    record.save(:validate => false)
  end
end

describe AssignableValues::ActiveRecord do

  describe '.assignable_values' do

    it 'should raise an error when not called with a block or :through option' do
      expect do
        Song.disposable_copy do
          assignable_values_for :genre
        end
      end.to raise_error(AssignableValues::NoValuesGiven)
    end

    it 'should raise an error when called with unsupported options' do
      expect do
        Song.disposable_copy do
          assignable_values_for :genre, unsupported_option: 42
        end
      end.to raise_error(AssignableValues::UnsupportedOption, 'The following options are not supported: :unsupported_option')
    end

    context 'when validating virtual attributes' do

      before :each do
        @klass = Song.disposable_copy do
          assignable_values_for :virtual_sub_genre do
            %w[pop rock]
          end

          assignable_values_for :virtual_multi_genres, :multiple => true, :allow_blank => true do
            %w[pop rock]
          end
        end
      end

      it 'should validate that the attribute is allowed' do
        @klass.new(:virtual_sub_genre => 'pop').should be_valid
        @klass.new(:virtual_sub_genre => 'disallowed value').should_not be_valid
      end

      it 'should not allow nil for the attribute value' do
        @klass.new(:virtual_sub_genre => nil).should_not be_valid
      end

      it 'should generate a method returning the humanized value' do
        song = @klass.new(:virtual_sub_genre => 'pop')
        song.humanized_virtual_sub_genre.should == 'Pop music'
        song.humanized_virtual_sub_genre('rock').should == 'Rock music'
        song.humanized_virtual_multi_genre('rock').should == 'Rock music'
      end

    end

    context 'when the options are passed as a hash' do
      before :each do
        @klass = Song.disposable_copy do
          assignable_values_for(:virtual_multi_genres, { :multiple => true, :allow_blank => true }) do
            %w[pop rock]
          end
        end
      end

      it 'should not raise an error' do
        @klass.new(:virtual_multi_genres => ['rock']).should be_valid
      end
    end

    context 'when validating virtual attributes with multiple: true' do

      context 'with allow_blank: false' do

        before :each do
          @klass = Song.disposable_copy do
            assignable_values_for :virtual_multi_genres, :multiple => true do
              %w[pop rock]
            end
          end
        end

        it 'should validate that the attribute is a subset' do
          @klass.new(:virtual_multi_genres => ['pop']).should be_valid
          @klass.new(:virtual_multi_genres => ['pop', 'rock']).should be_valid
          @klass.new(:virtual_multi_genres => ['pop', 'disallowed value']).should_not be_valid
        end

        it 'should not allow nil or [] for allow_blank: false' do
          @klass.new(:virtual_multi_genres => nil).should_not be_valid
          @klass.new(:virtual_multi_genres => []).should_not be_valid
        end

      end

      context 'with allow_blank: true' do

        before :each do
          @klass = Song.disposable_copy do
            assignable_values_for :virtual_multi_genres, :multiple => true, :allow_blank => true do
              %w[pop rock]
            end
          end
        end

        it 'should allow nil or [] for allow_blank: false' do
          @klass.new(:virtual_multi_genres => nil).should be_valid
          @klass.new(:virtual_multi_genres => []).should be_valid
        end

      end

    end

    context 'when validating scalar attributes' do

      context 'without options' do

        before :each do
          @klass = Song.disposable_copy do
            assignable_values_for :genre do
              %w[pop rock]
            end

            assignable_values_for :virtual_multi_genres, :multiple => true, :allow_blank => true do
              %w[pop rock]
            end
          end
        end

        it 'should validate that the attribute is allowed' do
          @klass.new(:genre => 'pop').should be_valid
          @klass.new(:genre => 'disallowed value').should_not be_valid
        end

        it 'should use the same error message as validates_inclusion_of' do
          record = @klass.new(:genre => 'disallowed value')
          record.valid?
          errors = record.errors[:genre]
          error = errors.respond_to?(:first) ? errors.first : errors # the return value sometimes was a string, sometimes an Array in Rails
          error.should == I18n.t('errors.messages.inclusion')
          error.should == 'is not included in the list'
        end

        it 'should not allow nil for the attribute value' do
          @klass.new(:genre => nil).should_not be_valid
        end

        it 'should allow a previously saved value even if that value is no longer allowed' do
          record = @klass.create!(:genre => 'pop')
          @klass.update_all(:genre => 'pretend previously valid value') # update without validations for the sake of this test
          record.reload.should be_valid
        end

        it 'should allow a previously saved, blank value even if that value is no longer allowed' do
          record = @klass.create!(:genre => 'pop')
          @klass.update_all(:genre => '') # update without validations for the sake of this test
          record.reload.should be_valid
        end

        it 'should not allow nil (the "previous value") if the record was never saved' do
          record = @klass.new(:genre => nil)
          # Show that nil is not assignable, even though `record.genre_was` is nil.
          record.should_not be_valid
        end

        it 'should generate a method returning the humanized value' do
          song = @klass.new(:genre => 'pop')
          song.humanized_genre.should == 'Pop music'
        end

        it 'should generate a method returning the humanized value, which is nil when the value is blank' do
          song = @klass.new
          song.genre = nil
          song.humanized_genre.should be_nil
          song.genre = ''
          song.humanized_genre.should be_nil
        end

        it 'should generate an instance method to retrieve the humanization of any given value' do
          song = @klass.new(:genre => 'pop')
          song.humanized_genre('rock').should == 'Rock music'
        end

        it 'should generate a class method to retrieve the humanization of any given value' do
          @klass.humanized_genre('rock').should == 'Rock music'
        end

        context 'for multiple: true' do
          it 'should raise when trying to humanize a value without an argument' do
            song = @klass.new
            proc { song.humanized_virtual_multi_genre }.should raise_error(ArgumentError)
          end

          it 'should generate an instance method to retrieve the humanization of any given value' do
            song = @klass.new(:genre => 'pop')
            song.humanized_virtual_multi_genre('rock').should == 'Rock music'
          end

          it 'should generate a class method to retrieve the humanization of any given value' do
            @klass.humanized_virtual_multi_genre('rock').should == 'Rock music'
          end

          it 'should generate an instance method to retrieve the humanizations of all current values' do
            song = @klass.new
            song.virtual_multi_genres = nil
            song.humanized_virtual_multi_genres.should == nil
            song.virtual_multi_genres = []
            song.humanized_virtual_multi_genres.should == []
            song.virtual_multi_genres = ['pop', 'rock']
            song.humanized_virtual_multi_genres.should == ['Pop music', 'Rock music']
          end
        end
      end

      context 'if the :allow_blank option is set to true' do

        before :each do
          @klass = Song.disposable_copy do
            assignable_values_for :genre, :allow_blank => true do
              %w[pop rock]
            end
          end
        end

        it 'should allow nil for the attribute value' do
          @klass.new(:genre => nil).should be_valid
        end

        it 'should allow an empty string as value' do
          @klass.new(:genre => '').should be_valid
        end

      end

      context 'if the :allow_blank option is set to a symbol that refers to an instance method' do

        before :each do
          @klass = Song.disposable_copy do

            attr_accessor :genre_may_be_blank

            assignable_values_for :genre, :allow_blank => :genre_may_be_blank do
              %w[pop rock]
            end

          end
        end

        it 'should call that method to determine if a blank value is allowed' do
          @klass.new(:genre => '', :genre_may_be_blank => true).should be_valid
          @klass.new(:genre => '', :genre_may_be_blank => false).should_not be_valid
        end

      end

      context 'if the :allow_blank option is set to a lambda' do

        before :each do
          @klass = Song.disposable_copy do

            attr_accessor :genre_may_be_blank

            assignable_values_for :genre, :allow_blank => lambda { genre_may_be_blank } do
              %w[pop rock]
            end

          end
        end

        it 'should evaluate that lambda in the record context to determine if a blank value is allowed' do
          @klass.new(:genre => '', :genre_may_be_blank => true).should be_valid
          @klass.new(:genre => '', :genre_may_be_blank => false).should_not be_valid
        end

      end

      context 'if the :message option is set to a string' do

        before :each do
          @klass = Song.disposable_copy do
            assignable_values_for :genre, :message => 'should be something different' do
              %w[pop rock]
            end
          end
        end

        it 'should use this string as a custom error message' do
          record = @klass.new(:genre => 'disallowed value')
          record.valid?
          errors = record.errors[:genre]
          error = errors.respond_to?(:first) ? errors.first : errors # the return value sometimes was a string, sometimes an Array in Rails
          error.should == 'should be something different'
        end

      end

    end

    context 'when validating scalar attributes with multiple: true' do

      context 'without options' do

        before :each do
          @klass = Song.disposable_copy do
            assignable_values_for :multi_genres, :multiple => true do
              %w[pop rock]
            end
          end
        end

        it 'should validate that the attribute is allowed' do
          @klass.new(:multi_genres => ['pop']).should be_valid
          @klass.new(:multi_genres => ['pop', 'rock']).should be_valid
          @klass.new(:multi_genres => ['pop', 'invalid value']).should_not be_valid
        end

        it 'should not allow a scalar attribute' do
          @klass.new(:multi_genres => 'pop').should_not be_valid
        end

        it 'should not allow nil or [] for the attribute value' do
          @klass.new(:multi_genres => nil).should_not be_valid
          @klass.new(:multi_genres => []).should_not be_valid
        end

        it 'should allow a subset of previously saved values even if that value is no longer allowed' do
          record = @klass.create!(:multi_genres => ['pop'])
          record.multi_genres = ['pretend', 'previously', 'valid', 'value']
          save_without_validation(record) # update without validation for the sake of this test
          record.reload.should be_valid
          record.multi_genres = ['valid', 'previously', 'pop']
          record.should be_valid
        end

        it 'should allow a previously saved, blank value even if that value is no longer allowed' do
          record = @klass.create!(:multi_genres => ['pop'])
          @klass.update_all(:multi_genres => []) # update without validations for the sake of this test
          record.reload.should be_valid
        end

      end

      context 'if the :allow_blank option is set to true' do

        before :each do
          @klass = Song.disposable_copy do
            assignable_values_for :multi_genres, :multiple => true, :allow_blank => true do
              %w[pop rock]
            end
          end
        end

        it 'should allow nil for the attribute value' do
          @klass.new(:multi_genres => nil).should be_valid
        end

        it 'should allow an empty array as value' do
          @klass.new(:multi_genres => []).should be_valid
        end

      end

    end

    context 'when validating scalar attributes from a store_accessor' do

      context 'without options' do

        before :each do
          @klass = Song.disposable_copy do
            store_accessor :metadata, :format

            assignable_values_for :format do
              %w[mp3 wav]
            end
          end
        end

        it 'should validate that the attribute is allowed' do
          @klass.new(:format => 'mp3').should be_valid
          @klass.new(:format => 'disallowed value').should_not be_valid
        end

        it 'should use the same error message as validates_inclusion_of' do
          record = @klass.new(:format => 'disallowed value')
          record.valid?
          errors = record.errors[:format]
          error = errors.respond_to?(:first) ? errors.first : errors # the return value sometimes was a string, sometimes an Array in Rails
          error.should == I18n.t('errors.messages.inclusion')
          error.should == 'is not included in the list'
        end

        it 'should not allow nil for the attribute value' do
          @klass.new(:format => nil).should_not be_valid
        end

        it 'should allow a previously saved value even if that value is no longer allowed' do
          record = @klass.create!(:format => 'mp3')

          @klass.update_all(metadata: { 'format' => 'pretend previously valid value' }) # update without validations for the sake of this test
          record.reload.should be_valid
        end

        it 'should allow a previously saved, blank format value even if that value is no longer allowed' do
          record = @klass.create!(:format => 'mp3')

          @klass.update_all(metadata: { 'format' => nil }) # update without validations for the sake of this test
          record.reload.should be_valid
        end

        it 'should not allow nil (the "previous value") if the record was never saved' do
          record = @klass.new(:format => nil)
          # Show that nil is not assignable, even though `record.genre_was` is nil.
          record.should_not be_valid
        end

        it 'should generate a method returning the humanized value' do
          song = @klass.new(:format => 'mp3')
          song.humanized_format.should == 'MP3-Codec'
        end

        it 'should generate a method returning the humanized value, which is nil when the value is blank' do
          song = @klass.new
          song.format = nil
          song.humanized_format.should be_nil
          song.format = ''
          song.humanized_format.should be_nil
        end

        it 'should generate an instance method to retrieve the humanization of any given value' do
          song = @klass.new(:format => 'mp3')
          song.humanized_format('wav').should == 'WAV-Codec'
        end

        it 'should generate a class method to retrieve the humanization of any given value' do
          @klass.humanized_format('wav').should == 'WAV-Codec'
        end

        context 'for multiple: true' do
          before :each do
            @klass = Song.disposable_copy do
              store_accessor :metadata, :instruments

              assignable_values_for :instruments, multiple: true do
                %w[piano drums guitar]
              end
            end
          end

          it 'should raise when trying to humanize a value without an argument' do
            song = @klass.new
            proc { song.humanized_instrument }.should raise_error(ArgumentError)
          end

          it 'should generate an instance method to retrieve the humanization of any given value' do
            song = @klass.new(:instruments => 'drums')
            song.humanized_instrument('piano').should == 'Piano'
          end

          it 'should generate a class method to retrieve the humanization of any given value' do
            @klass.humanized_instrument('piano').should == 'Piano'
          end

          it 'should generate an instance method to retrieve the humanizations of all current values' do
            song = @klass.new
            song.instruments = nil
            song.humanized_instruments.should == nil
            song.instruments = []
            song.humanized_instruments.should == []
            song.instruments = ['piano', 'drums']
            song.humanized_instruments.should == ['Piano', 'Drums']
          end
        end
      end

      context 'if the :allow_blank option is set to true' do

        before :each do
          @klass = Song.disposable_copy do

            store_accessor :metadata, :format

            assignable_values_for :format, :allow_blank => true do
              %w[mp3 wav]
            end
          end
        end

        it 'should allow nil for the attribute value' do
          @klass.new(:format => nil).should be_valid
        end

        it 'should allow an empty string as value' do
          @klass.new(:format => '').should be_valid
        end

      end

      context 'if the :allow_blank option is set to a symbol that refers to an instance method' do

        before :each do
          @klass = Song.disposable_copy do

            store_accessor :metadata, :format

            attr_accessor :format_may_be_blank

            assignable_values_for :format, :allow_blank => :format_may_be_blank do
              %w[mp3 wav]
            end

          end
        end

        it 'should call that method to determine if a blank value is allowed' do
          @klass.new(:format => '', :format_may_be_blank => true).should be_valid
          @klass.new(:format => '', :format_may_be_blank => false).should_not be_valid
        end

      end

      context 'if the :allow_blank option is set to a lambda' do

        before :each do
          @klass = Song.disposable_copy do

            store_accessor :metadata, :format

            attr_accessor :format_may_be_blank

            assignable_values_for :format, :allow_blank => lambda { format_may_be_blank } do
              %w[mp3 wav]
            end

          end
        end

        it 'should evaluate that lambda in the record context to determine if a blank value is allowed' do
          @klass.new(:format => '', :format_may_be_blank => true).should be_valid
          @klass.new(:format => '', :format_may_be_blank => false).should_not be_valid
        end

      end

      context 'if the :message option is set to a string' do

        before :each do
          @klass = Song.disposable_copy do

            store_accessor :metadata, :format

            assignable_values_for :format, :message => 'should be something different' do
              %w[mp3 wav]
            end
          end
        end

        it 'should use this string as a custom error message' do
          record = @klass.new(:format => 'disallowed value')
          record.valid?
          errors = record.errors[:format]
          error = errors.respond_to?(:first) ? errors.first : errors # the return value sometimes was a string, sometimes an Array in Rails
          error.should == 'should be something different'
        end

      end

    end

    context 'when validating belongs_to associations' do

      it 'should validate that the association is allowed' do
        allowed_association = Artist.create!
        disallowed_association = Artist.create!
        klass = Song.disposable_copy do
          assignable_values_for :artist do
            [allowed_association]
          end
        end
        klass.new(:artist => allowed_association).should be_valid
        klass.new(:artist => disallowed_association).should_not be_valid
      end

      it 'should attach errors to the foreign key of the association, not the association itself ' do
        allowed_association = Artist.create!
        disallowed_association = Artist.create!
        klass = Song.disposable_copy do
          assignable_values_for :artist do
            [allowed_association]
          end
        end
        record = klass.new(:artist => disallowed_association)
        record.valid?
        errors = record.errors[:artist_id]
        error = errors.respond_to?(:first) ? errors.first : errors # the return value sometimes was a string, sometimes an Array in Rails
        error.should == I18n.t('errors.messages.inclusion')
      end

      it 'uses the defined foreign key of the association' do
        klass = Song.disposable_copy do
          belongs_to :creator, :foreign_key => 'artist_id', :class_name => 'Artist'

          assignable_values_for :creator do
            []
          end
        end

        song = klass.new(:creator => Artist.new)
        song.valid?
        song.errors[:artist_id].should be_present
      end

      it 'should allow a nil association if the :allow_blank option is set' do
        klass = Song.disposable_copy do
          assignable_values_for :artist, :allow_blank => true do
            []
          end
        end
        record = klass.new
        record.artist.should be_nil
        record.should be_valid
      end

      it 'should allow a previously saved association, even if that association is no longer allowed' do
        allowed_association = Artist.create!
        disallowed_association = Artist.create!
        klass = Song.disposable_copy
        record = klass.create!(:artist => disallowed_association)
        klass.class_eval do
          assignable_values_for :artist do
            [allowed_association]
          end
        end
        record.should be_valid
      end

      it 'should not request the list of assignable values during validation if the association has not changed' do
        allowed_association = Artist.create!
        klass = Song.disposable_copy
        record = klass.create!(:artist => allowed_association)

        request_count = 0

        klass.class_eval do
          assignable_values_for :artist do
            request_count += 1
            [allowed_association]
          end
        end

        record.reload
        request_count.should == 0
        record.year = 1975 # change any other attribute to make the record dirty
        record.valid?
        request_count.should == 0
      end

      it 'should allow nil for an association if the record was saved before with a nil association' do
        allowed_association = Artist.create!
        klass = Song.disposable_copy
        record = klass.create!(:artist => nil)
        klass.class_eval do
          assignable_values_for :artist do
            [allowed_association]
          end
        end
        record.should be_valid
      end

      it 'should not allow nil for an association (the "previously saved value") if the record is new' do
        allowed_association = Artist.create!
        klass = Song.disposable_copy
        record = klass.new(:artist => nil)
        klass.class_eval do
          assignable_values_for :artist do
            [allowed_association]
          end
        end
        record.should_not be_valid
      end

      it "should not load a previously saved association if the association's foreign key hasn't changed" do
        association = Artist.create!
        klass = Song.disposable_copy do
          assignable_values_for :artist do
            [association] # This example doesn't care about what's assignable. We're only interested in behavior up to the validation.
          end
        end
        record = klass.create!(:artist => association)
        Artist.should_not_receive(:find_by_id)
        record.valid?
      end

      it 'should not fail or allow nil if a previously saved association no longer exists in the database' do
        allowed_association = Artist.create!
        klass = Song.disposable_copy do
          assignable_values_for :artist do
            [allowed_association]
          end
        end
        record = klass.new
        record.stub :artist_id_was => -1
        record.should_not be_valid
      end

      it 'should uncache a stale association before validating' do
        klass = Song.disposable_copy do
          assignable_values_for :artist do
            [] # This example doesn't care about what's assignable. We're only interested in behavior up to the validation.
          end
        end
        association = Artist.create!
        record = klass.new
        record.stub(:artist => association, :artist_id => -1) # This is a stale association: The associated object's id doesn't match the foreign key. This can happen in Rails 2, not Rails 3.
        record.should_receive(:artist).ordered.and_return(association)
        record.valid?
      end

      it 'should not uncache a fresh association before validating' do
        klass = Song.disposable_copy do
          assignable_values_for :artist do
            [] # This example doesn't care about what's assignable. We're only interested in behavior up to the validation.
          end
        end
        association = Artist.create!
        record = klass.new
        record.stub(:artist => association, :artist_id => association.id) # This is a fresh association: The associated object's id matches the foreign key.
        record.should_receive(:artist).with(no_args).and_return(association)
        record.valid?
      end

      context 'when assignable values are provided as an ActiveRecord scope' do
        MyArtist = Artist.disposable_copy
        let(:klass) { Song.disposable_copy }

        before do
          klass.class_eval do
            assignable_values_for :artist do
              if ::ActiveRecord::VERSION::MAJOR < 4
                MyArtist.scoped({})
              else
                MyArtist.all
              end
            end
          end
        end

        it 'allows assigning a record from the scope' do
          artist = MyArtist.create!
          song = klass.new(:artist => artist)
          song.should be_valid
        end

        it 'will not crash during validation when the assigned value is nil' do
          song = klass.new
          expect { song.valid? }.to_not raise_error
          song.errors[:artist_id].should be_present
        end

        it 'should not load all records into memory' do
          unless ::ActiveRecord::VERSION::MAJOR < 3 # somehow rails 2 still initializes Objects during the scope.exists?-call
            initialized_artists_count = 0

            MyArtist.class_eval do
              after_initialize :increase_initialized_count

              define_method :increase_initialized_count do
                initialized_artists_count += 1
              end
            end

            artist = MyArtist.create!
            initialized_artists_count.should == 1

            song = klass.new(:artist => artist)

            song.valid?
            initialized_artists_count.should == 1

            song.assignable_artists
            initialized_artists_count.should == 1

            song.assignable_artists.to_a
            initialized_artists_count.should == 2
          end
        end
      end

    end

    context 'when delegating using the :through option' do

      it 'should obtain allowed values from a method with the given name' do
        klass = Song.disposable_copy do
          assignable_values_for :genre, :through => :delegate
          def delegate
            Class.new do
              def assignable_song_genres
                %w[pop rock]
              end
            end.new
          end
        end
        klass.new(:genre => 'pop').should be_valid
        klass.new(:genre => 'disallowed value').should_not be_valid
      end

      it 'should be able to delegate to a lambda, which is evaluated in the context of the record instance' do
        klass = Song.disposable_copy do
          assignable_values_for :genre, :through => lambda { delegate }
          def delegate
            Class.new do
              def assignable_song_genres
                %w[pop rock]
              end
            end.new
          end
        end

        klass.new(:genre => 'pop').should be_valid
        klass.new(:genre => 'disallowed value').should_not be_valid
      end

      it 'should generate a legal getter name for a namespaced model (bugfix)' do
        klass = Recording::Vinyl.disposable_copy do
          assignable_values_for :year, :through => :delegate
          def delegate
            Class.new do
              def assignable_recording_vinyl_years
                [1977, 1980, 1983]
              end
            end.new
          end
        end
        klass.new.assignable_years.should == [1977, 1980, 1983]
      end

      it 'should not request the list of assignable values during validation if the association has not changed' do
        allowed_association = Artist.create!
        klass = Song.disposable_copy
        request_count = 0

        delegate = Class.new do
          define_method :assignable_song_artists do
            request_count += 1
            [allowed_association]
          end
        end.new

        record = klass.create!(:artist => allowed_association)

        klass.class_eval do
          assignable_values_for :artist, :through => lambda { delegate }
        end

        request_count.should == 0

        record.reload
        record.year = 1975 # change any other attribute to make the record dirty
        record.valid?
        request_count.should == 0
      end

      context 'when the delegation method returns nil' do
        let(:klass) do
          Song.disposable_copy do
            assignable_values_for :genre, :through => proc { nil }
          end
        end

        it 'should skip the validation' do
          klass.new(:genre => 'pop').should be_valid
        end

        it 'should still be able to humanize values on the instance' do
          klass.new(:genre => 'pop').humanized_genre.should == 'Pop music'
        end
      end

    end

    context 'with :default option' do

      it 'should allow to set a default' do
        klass = Song.disposable_copy do
          assignable_values_for :genre, :default => 'pop' do
            %w[pop rock]
          end
        end
        klass.new.genre.should == 'pop'
      end

      it 'should allow to set a default through a lambda' do
        klass = Song.disposable_copy do
          assignable_values_for :genre, :default => lambda { 'pop' } do
            %w[pop rock]
          end
        end
        klass.new.genre.should == 'pop'
      end

      it 'should evaluate a lambda default in the context of the record instance' do
        klass = Song.disposable_copy do
          assignable_values_for :genre, :default => lambda { default_genre } do
            %w[pop rock]
          end
          def default_genre
            'pop'
          end
        end
        klass.new.genre.should == 'pop'
      end

    end

    context 'with :secondary_default option' do

      it 'should set a secondary default value if the primary value is not assignable' do
        klass = Song.disposable_copy do
          assignable_values_for :genre, :default => 'techno', :secondary_default => 'rock' do
            %w[pop rock]
          end
        end
        klass.new.genre.should == 'rock'
      end

      it 'should not change the default value if the default value is assignable' do
        klass = Song.disposable_copy do
          assignable_values_for :genre, :default => 'pop', :secondary_default => 'rock' do
            %w[pop rock]
          end
        end
        klass.new.genre.should == 'pop'
      end

      it "should not change the primary default if the secondary default value isn't assignable either" do
        klass = Song.disposable_copy do
          assignable_values_for :genre, :default => 'techno', :secondary_default => 'jazz' do
            %w[pop rock]
          end
        end
        klass.new.genre.should == 'techno'
      end

      it 'should raise an error if used without a :default option' do
        expect do
          Song.disposable_copy do
            assignable_values_for :genre, :secondary_default => 'pop' do
              %w[pop rock]
            end
          end
        end.to raise_error(AssignableValues::NoDefault)
      end

      it 'should allow to set a secondary default through a lambda' do
        klass = Song.disposable_copy do
          assignable_values_for :genre, :default => 'techno', :secondary_default => lambda { 'pop' } do
            %w[pop rock]
          end
        end
        klass.new.genre.should == 'pop'
      end

      it 'should evaluate a secondary lambda default in the context of the record instance' do
        klass = Song.disposable_copy do
          assignable_values_for :genre, :default => 'techno', :secondary_default => lambda { default_genre } do
            %w[pop rock]
          end
          def default_genre
            'pop'
          end
        end
        klass.new.genre.should == 'pop'
      end

      it "should not raise an error or change the primary default if assignable values are retrieved through a delegate, and the delegate is nil" do
        klass = Song.disposable_copy do
          assignable_values_for :genre, :default => 'techno', :secondary_default => 'pop', :through => lambda { nil }
        end
        expect do
          klass.new.genre.should == 'techno'
        end.to_not raise_error
      end

      it 'should not cause the list of assignable values to be evaluated if the :secondary_default option is not used' do
        klass = Song.disposable_copy do
          assignable_values_for :genre, :default => 'techno' do
            raise "block called!"
          end
        end
        expect do
          klass.new.genre.should == 'techno'
        end.to_not raise_error
      end

    end

    context 'when generating methods to list assignable values' do

      it 'should generate an instance method returning a list of assignable values' do
        klass = Song.disposable_copy do
          assignable_values_for :genre do
            %w[pop rock]
          end
        end
        klass.new.assignable_genres.should == %w[pop rock]
      end

      it 'should work with ranges' do
        klass = Song.disposable_copy do
          assignable_values_for :year do
            1999..2001
          end
        end
        klass.new.assignable_years.should == [1999, 2000, 2001]
      end

      it 'should evaluate the value block in the context of the record instance' do
        klass = Song.disposable_copy do
          assignable_values_for :genre do
            genres
          end
          def genres
            %w[pop rock]
          end
        end
        klass.new.assignable_genres.should == %w[pop rock]
      end

      it 'returns an array when the value block returns a single value' do
        klass = Song.disposable_copy do
          assignable_values_for :genre do
            'techno'
          end
        end

        klass.new.assignable_genres.should == ['techno']
      end

      it 'returns an empty array when the value block returns nothing' do
        klass = Song.disposable_copy do
          assignable_values_for :genre do
            nil
          end
        end

        klass.new.assignable_genres.should == []
      end

      it 'should not return saved value twice (BUGFIX)' do
        klass = Song.disposable_copy do
          assignable_values_for :multi_genres, :multiple => true do
            %w[pop rock]
          end
        end
        record = klass.create!(:multi_genres => ['pop'])
        record.assignable_multi_genres.should eq ['pop', 'rock']
      end

      it 'should prepend a previously saved value to the top of the list, even if is no longer allowed' do
        klass = Song.disposable_copy do
          assignable_values_for :genre do
            %w[pop rock]
          end

          assignable_values_for :multi_genres, :multiple => true do
            %w[pop rock]
          end
        end
        record = klass.create!(:genre => 'pop', :multi_genres => ['rock'])
        klass.update_all(:genre => 'ballad') # update without validation for the sake of this test
        record.reload.assignable_genres.should == %w[ballad pop rock]

        humanized_genres = record.humanized_assignable_genres
        humanized_genres.collect(&:value).should == %w[ballad pop rock]
        humanized_genres.collect(&:humanized).should == ['Ballad', 'Pop music', 'Rock music']
        humanized_genres.collect(&:to_s).should == ['Ballad', 'Pop music', 'Rock music']

        record.multi_genres = %w[ballad classic]
        save_without_validation(record) # update without validation for the sake of this test
        record.reload.multi_genres.should == %w[ballad classic]

        humanized_multi_genres = record.humanized_assignable_multi_genres
        humanized_multi_genres.collect(&:value).should == %w[ballad classic pop rock]
        humanized_multi_genres.collect(&:humanized).should == ['Ballad', 'Classic', 'Pop music', 'Rock music']
        humanized_multi_genres.collect(&:to_s).should == ['Ballad', 'Classic', 'Pop music', 'Rock music']
      end

      it 'should not prepend a previously saved value to the top of the list if it is still allowed (bugfix)' do
        klass = Song.disposable_copy do
          assignable_values_for :genre do
            %w[pop rock]
          end
        end
        record = klass.create!(:genre => 'rock')
        record.assignable_genres.should == %w[pop rock]
      end

      it "should not prepend a previously saved blank value to the top of the list (because our forms already have collection_select with include_blank: '<prompt>')" do
        klass = Song.disposable_copy do
          assignable_values_for :genre do
            %w[pop rock]
          end
        end
        record = klass.create!(:genre => 'pop')
        klass.update_all(:genre => '') # update without validation for the sake of this test
        record.reload.assignable_genres.should == ['pop', 'rock']
      end

      it 'should not prepend nil to the top of the list if the record was never saved' do
        klass = Song.disposable_copy do
          assignable_values_for :genre do
            %w[pop rock]
          end
        end
        record = klass.new(:genre => 'pop')
        record.genre_was.should be_nil
        record.assignable_genres.should == ['pop', 'rock']
      end

      it 'should allow omitting a previously saved value with :include_old_value => false option' do
        klass = Song.disposable_copy do
          assignable_values_for :genre do
            %w[pop rock]
          end

          assignable_values_for :multi_genres, :multiple => true do
            %w[pop rock]
          end
        end
        record = klass.create!(:genre => 'pop', :multi_genres => ['rock'])
        klass.update_all(:genre => 'ballad') # update without validation for the sake of this test
        record.reload.assignable_genres(:include_old_value => false).should == %w[pop rock]

        humanized_genres = record.humanized_assignable_genres(:include_old_value => false)
        humanized_genres.collect(&:value).should == %w[pop rock]
        humanized_genres.collect(&:humanized).should == ['Pop music', 'Rock music']
        humanized_genres.collect(&:to_s).should == ['Pop music', 'Rock music']

        record.multi_genres = %w[ballad classic]
        save_without_validation(record) # update without validation for the sake of this test
        record.reload.multi_genres.should == %w[ballad classic]

        humanized_multi_genres = record.humanized_assignable_multi_genres(:include_old_value => false)
        humanized_multi_genres.collect(&:value).should == %w[pop rock]
        humanized_multi_genres.collect(&:humanized).should == ['Pop music', 'Rock music']
        humanized_multi_genres.collect(&:to_s).should == ['Pop music', 'Rock music']
      end

      it 'should allow omitting a previously saved association' do
        allowed_association = Artist.create!
        disallowed_association = Artist.create!
        klass = Song.disposable_copy

        record = klass.create!(:artist => disallowed_association)
        klass.class_eval do
          assignable_values_for :artist do
            [allowed_association]
          end
        end
        record.assignable_artists(:include_old_value => false).should =~ [allowed_association]
      end

      context 'if the :allow_blank option is set to true' do

        before :each do
          @klass = Song.disposable_copy do
            assignable_values_for :genre, :allow_blank => true do
              %w[pop rock]
            end
          end
        end

        it "should not prepend nil to the list for an unsaved record (because we'd rather use include_blank: '<prompt>' in collection_select)" do
          record = @klass.new
          record.assignable_genres.should == ['pop', 'rock']
        end

      end

      context 'humanization' do

        it 'should define a method that return pairs of values and their humanization' do
          klass = Song.disposable_copy do
            assignable_values_for :genre do
              %w[pop rock]
            end

            assignable_values_for :multi_genres, :multiple => true do
              %w[pop rock]
            end
          end
          genres = klass.new.humanized_assignable_genres
          genres.collect(&:value).should == ['pop', 'rock']
          genres.collect(&:humanized).should == ['Pop music', 'Rock music']
          genres.collect(&:to_s).should == ['Pop music', 'Rock music']

          multi_genres = klass.new.humanized_assignable_multi_genres
          multi_genres.collect(&:humanized).should == ['Pop music', 'Rock music']
        end

        it 'should use String#humanize as a default translation' do
          klass = Song.disposable_copy do
            assignable_values_for :genre do
              %w[electronic]
            end
          end
          klass.new.humanized_assignable_genres.collect(&:humanized).should == ['Electronic']
        end

        it 'should allow to define humanizations for values that are not strings' do
          klass = Song.disposable_copy do
            assignable_values_for :year do
              [1977, 1980, 1983]
            end
          end
          years = klass.new.humanized_assignable_years
          years.collect(&:value).should == [1977, 1980, 1983]
          years.collect(&:humanized).should == ['The year a new hope was born', 'The year the Empire struck back', 'The year the Jedi returned']
        end

        it 'should properly look up humanizations for namespaced models' do
          klass = Recording::Vinyl.disposable_copy do
            assignable_values_for :year do
              [1977, 1980, 1983]
            end
          end
          years = klass.new.humanized_assignable_years
          years.collect(&:humanized).should == ['The year a new hope was born', 'The year the Empire struck back', 'The year the Jedi returned']
        end

        context 'when inheriting from a model with defined assignable_values' do

          let(:base_class) do
            Class.new(Song) do
              assignable_values_for :year do
                [1977, 1980, 1983]
              end
            end
          end

          it 'allows to override humanization for inherited values' do
            Song::SeriousRepresentation = Class.new(base_class)

            years = Song::SeriousRepresentation.new.humanized_assignable_years
            years.collect(&:humanized).should == ['year 1977', 'year 1980', 'year 1983']
          end

          it 'looks up humanization in parent classes if the translation is not overridden' do
            Song::Extension = Class.new(base_class)
            Song::ExtendedExtension = Class.new(Song::Extension)

            years_1 = Song::Extension.new.humanized_assignable_years
            years_1.collect(&:humanized).should == ['The year a new hope was born', 'The year the Empire struck back', 'The year the Jedi returned']

            years_2 = Song::ExtendedExtension.new.humanized_assignable_years
            years_2.collect(&:humanized).should == ['The year a new hope was born', 'The year the Empire struck back', 'The year the Jedi returned']
          end

        end

        context 'legacy methods for API compatibility' do

          it 'should define a method that return pairs of values and their humanization' do
            klass = Song.disposable_copy do
              assignable_values_for :genre do
                %w[pop rock]
              end
            end
            ActiveSupport::Deprecation.should_receive(:warn)
            genres = klass.new.humanized_genres
            genres.collect(&:humanized).should == ['Pop music', 'Rock music']
          end

          it "should define a method #humanized on assignable string values, which return up the value's' translation" do
            klass = Song.disposable_copy do
              assignable_values_for :genre do
                %w[pop rock]
              end
            end
            ActiveSupport::Deprecation.should_receive(:warn).at_least(:once)
            klass.new.assignable_genres.collect(&:humanized).should == ['Pop music', 'Rock music']
          end

          it 'should not define a method #humanized on values that are not strings' do
            klass = Song.disposable_copy do
              assignable_values_for :year do
                [1999, 2000, 2001]
              end
            end
            years = klass.new.assignable_years
            years.should == [1999, 2000, 2001]
            years.first.should_not respond_to(:humanized)
          end

        end

      end

      context 'with :through option' do

        it 'should retrieve assignable values from the given method' do
          klass = Song.disposable_copy do
            assignable_values_for :genre, :through => :delegate
            def delegate
              @delegate ||= 'delegate'
            end
          end
          record = klass.new
          record.delegate.should_receive(:assignable_song_genres).and_return %w[pop rock]
          record.assignable_genres.should == %w[pop rock]
        end

        it "should pass the record to the given method if the delegate's query method takes an argument" do
          delegate = Object.new
          def delegate.assignable_song_genres(record)
            record_received(record)
            %w[pop rock]
          end
          klass = Song.disposable_copy do
            assignable_values_for :genre, :through => :delegate
            define_method :delegate do
              delegate
            end
          end
          record = klass.new
          delegate.should_receive(:record_received).with(record)
          record.assignable_genres.should ==  %w[pop rock]
        end

        it "should call the given method on the delegate if the delegate's query method takes no arguments" do
          delegate = Object.new
          def delegate.assignable_song_genres
            no_record_received
            %w[pop rock]
          end
          klass = Song.disposable_copy do
            assignable_values_for :genre, :through => :delegate
            define_method :delegate do
              delegate
            end
          end
          record = klass.new
          delegate.should_receive(:no_record_received)
          record.assignable_genres.should ==  %w[pop rock]
        end

        it "should pass the record to the given method if the delegate's query method takes variable arguments" do
          delegate = Object.new
          def delegate.assignable_song_genres(*records)
            record_received(*records)
            %w[pop rock]
          end
          klass = Song.disposable_copy do
            assignable_values_for :genre, :through => :delegate
            define_method :delegate do
              delegate
            end
          end
          record = klass.new
          delegate.should_receive(:record_received).with(record)
          record.assignable_genres.should ==  %w[pop rock]
        end

        it "should raise an error if the delegate's query method takes more than one argument" do
          delegate = Object.new
          def delegate.assignable_song_genres(record, other_arg)
            %w[pop rock]
          end
          klass = Song.disposable_copy do
            assignable_values_for :genre, :through => :delegate
            define_method :delegate do
              delegate
            end
          end
          record = klass.new
          expect{record.assignable_genres}.to raise_error(ArgumentError)
        end

        it 'should raise an error if the given method returns nil' do
          klass = Song.disposable_copy do
            assignable_values_for :genre, :through => :delegate
            def delegate
              nil
            end
          end
          expect { klass.new.assignable_genres }.to raise_error(AssignableValues::DelegateUnavailable)
        end
      end
    end
  end
end