Move validations in ActiveModel to validators, however all validatity checks are still in the class method.

12 files changed, 200 insertions, 157 deletions

diff --git a/activemodel/lib/active_model.rb b/activemodel/lib/active_model.rb
index e0de27b96d..6aa80da23f 100644
--- a/activemodel/lib/active_model.rb
+++ b/activemodel/lib/active_model.rb
@@ -35,9 +35,9 @@ module ActiveModel
   autoload :Dirty
   autoload :Errors
   autoload :Lint
-  autoload :Name,         'active_model/naming'
+  autoload :Name, 'active_model/naming'
   autoload :Naming
-  autoload :Observer,     'active_model/observing'
+  autoload :Observer, 'active_model/observing'
   autoload :Observing
   autoload :Serialization
   autoload :StateMachine
@@ -45,6 +45,7 @@ module ActiveModel
   autoload :Validations
   autoload :ValidationsRepairHelper
   autoload :Validator
+  autoload :EachValidator, 'active_model/validator'
   autoload :VERSION
 
   module Serializers
diff --git a/activemodel/lib/active_model/validations/acceptance.rb b/activemodel/lib/active_model/validations/acceptance.rb
index b65c9b933d..a5de58cd41 100644
--- a/activemodel/lib/active_model/validations/acceptance.rb
+++ b/activemodel/lib/active_model/validations/acceptance.rb
@@ -1,5 +1,13 @@
 module ActiveModel
   module Validations
+    class AcceptanceValidator < EachValidator
+      def validate_each(record, attribute, value)
+        unless value == options[:accept]
+          record.errors.add(attribute, :accepted, :default => options[:message])
+        end
+      end
+    end
+
     module ClassMethods
       # Encapsulates the pattern of wanting to validate the acceptance of a terms of service check box (or similar agreement). Example:
       #
@@ -25,8 +33,8 @@ module ActiveModel
       #   not occur (e.g. <tt>:unless => :skip_validation</tt>, or <tt>:unless => Proc.new { |user| user.signup_step <= 2 }</tt>).  The
       #   method, proc or string should return or evaluate to a true or false value.
       def validates_acceptance_of(*attr_names)
-        configuration = { :allow_nil => true, :accept => "1" }
-        configuration.update(attr_names.extract_options!)
+        options = { :allow_nil => true, :accept => "1" }
+        options.update(attr_names.extract_options!)
 
         db_cols = begin
           column_names
@@ -37,11 +45,7 @@ module ActiveModel
         names = attr_names.reject { |name| db_cols.include?(name.to_s) }
         attr_accessor(*names)
 
-        validates_each(attr_names,configuration) do |record, attr_name, value|
-          unless value == configuration[:accept]
-            record.errors.add(attr_name, :accepted, :default => configuration[:message])
-          end
-        end
+        validates_with AcceptanceValidator, options.merge(:attributes => attr_names)
       end
     end
   end
diff --git a/activemodel/lib/active_model/validations/confirmation.rb b/activemodel/lib/active_model/validations/confirmation.rb
index d414224dd2..b06effdceb 100644
--- a/activemodel/lib/active_model/validations/confirmation.rb
+++ b/activemodel/lib/active_model/validations/confirmation.rb
@@ -1,5 +1,13 @@
 module ActiveModel
   module Validations
+    class ConfirmationValidator < EachValidator
+      def validate_each(record, attribute, value)
+        confirmed = record.send(:"#{attribute}_confirmation")
+        return if confirmed.nil? || value == confirmed
+        record.errors.add(attribute, :confirmation, :default => options[:message])
+      end
+    end
+
     module ClassMethods
       # Encapsulates the pattern of wanting to validate a password or email address field with a confirmation. Example:
       #
@@ -30,15 +38,9 @@ module ActiveModel
       #   not occur (e.g. <tt>:unless => :skip_validation</tt>, or <tt>:unless => Proc.new { |user| user.signup_step <= 2 }</tt>).  The
       #   method, proc or string should return or evaluate to a true or false value.
       def validates_confirmation_of(*attr_names)
-        configuration = attr_names.extract_options!
-
-        attr_accessor(*(attr_names.map { |n| "#{n}_confirmation" }))
-
-        validates_each(attr_names, configuration) do |record, attr_name, value|
-          unless record.send("#{attr_name}_confirmation").nil? or value == record.send("#{attr_name}_confirmation")
-            record.errors.add(attr_name, :confirmation, :default => configuration[:message])
-          end
-        end
+        options = attr_names.extract_options!
+        attr_accessor(*(attr_names.map { |n| :"#{n}_confirmation" }))
+        validates_with ConfirmationValidator, options.merge(:attributes => attr_names)
       end
     end
   end
diff --git a/activemodel/lib/active_model/validations/exclusion.rb b/activemodel/lib/active_model/validations/exclusion.rb
index 2cfdec97a5..209b1c76f9 100644
--- a/activemodel/lib/active_model/validations/exclusion.rb
+++ b/activemodel/lib/active_model/validations/exclusion.rb
@@ -1,5 +1,12 @@
 module ActiveModel
   module Validations
+    class ExclusionValidator < EachValidator
+      def validate_each(record, attribute, value)
+        return unless options[:in].include?(value)
+        record.errors.add(attribute, :exclusion, :default => options[:message], :value => value)
+      end
+    end
+
     module ClassMethods
       # Validates that the value of the specified attribute is not in a particular enumerable object.
       #
@@ -21,17 +28,13 @@ module ActiveModel
       #   not occur (e.g. <tt>:unless => :skip_validation</tt>, or <tt>:unless => Proc.new { |user| user.signup_step <= 2 }</tt>).  The
       #   method, proc or string should return or evaluate to a true or false value.
       def validates_exclusion_of(*attr_names)
-        configuration = attr_names.extract_options!
-
-        enum = configuration[:in] || configuration[:within]
+        options = attr_names.extract_options!
+        options[:in] ||= options.delete(:within)
 
-        raise(ArgumentError, "An object with the method include? is required must be supplied as the :in option of the configuration hash") unless enum.respond_to?(:include?)
+        raise ArgumentError, "An object with the method include? is required must be supplied as the " <<
+                             ":in option of the configuration hash" unless options[:in].respond_to?(:include?)
 
-        validates_each(attr_names, configuration) do |record, attr_name, value|
-          if enum.include?(value)
-            record.errors.add(attr_name, :exclusion, :default => configuration[:message], :value => value)
-          end
-        end
+        validates_with ExclusionValidator, options.merge(:attributes => attr_names)
       end
     end
   end
diff --git a/activemodel/lib/active_model/validations/format.rb b/activemodel/lib/active_model/validations/format.rb
index c670dafc7c..d5427c2b03 100644
--- a/activemodel/lib/active_model/validations/format.rb
+++ b/activemodel/lib/active_model/validations/format.rb
@@ -1,5 +1,15 @@
 module ActiveModel
   module Validations
+    class FormatValidator < EachValidator
+      def validate_each(record, attribute, value)
+        if options[:with] && value.to_s !~ options[:with]
+          record.errors.add(attribute, :invalid, :default => options[:message], :value => value)
+        elsif options[:without] && value.to_s =~ options[:without]
+          record.errors.add(attribute, :invalid, :default => options[:message], :value => value)
+        end
+      end
+    end
+
     module ClassMethods
       # Validates whether the value of the specified attribute is of the correct form, going by the regular expression provided.
       # You can require that the attribute matches the regular expression:
@@ -33,29 +43,21 @@ module ActiveModel
       #   not occur (e.g. <tt>:unless => :skip_validation</tt>, or <tt>:unless => Proc.new { |user| user.signup_step <= 2 }</tt>).  The
       #   method, proc or string should return or evaluate to a true or false value.
       def validates_format_of(*attr_names)
-        configuration = attr_names.extract_options!
+        options = attr_names.extract_options!
 
-        unless configuration.include?(:with) ^ configuration.include?(:without)  # ^ == xor, or "exclusive or"
+        unless options.include?(:with) ^ options.include?(:without)  # ^ == xor, or "exclusive or"
           raise ArgumentError, "Either :with or :without must be supplied (but not both)"
         end
 
-        if configuration[:with] && !configuration[:with].is_a?(Regexp)
+        if options[:with] && !options[:with].is_a?(Regexp)
           raise ArgumentError, "A regular expression must be supplied as the :with option of the configuration hash"
         end
 
-        if configuration[:without] && !configuration[:without].is_a?(Regexp)
+        if options[:without] && !options[:without].is_a?(Regexp)
           raise ArgumentError, "A regular expression must be supplied as the :without option of the configuration hash"
         end
 
-        if configuration[:with]
-          validates_each(attr_names, configuration) do |record, attr_name, value|
-            record.errors.add(attr_name, :invalid, :default => configuration[:message], :value => value) if value.to_s !~ configuration[:with]
-          end
-        elsif configuration[:without]
-          validates_each(attr_names, configuration) do |record, attr_name, value|
-            record.errors.add(attr_name, :invalid, :default => configuration[:message], :value => value) if value.to_s =~ configuration[:without]
-          end
-        end
+        validates_with FormatValidator, options.merge(:attributes => attr_names)
       end
     end
   end
diff --git a/activemodel/lib/active_model/validations/inclusion.rb b/activemodel/lib/active_model/validations/inclusion.rb
index 0d7dc5cd64..d42c95357c 100644
--- a/activemodel/lib/active_model/validations/inclusion.rb
+++ b/activemodel/lib/active_model/validations/inclusion.rb
@@ -1,5 +1,12 @@
 module ActiveModel
   module Validations
+    class InclusionValidator < EachValidator
+      def validate_each(record, attribute, value)
+        return if options[:in].include?(value)
+        record.errors.add(attribute, :inclusion, :default => options[:message], :value => value)
+      end
+    end
+
     module ClassMethods
       # Validates whether the value of the specified attribute is available in a particular enumerable object.
       #
@@ -21,17 +28,13 @@ module ActiveModel
       #   not occur (e.g. <tt>:unless => :skip_validation</tt>, or <tt>:unless => Proc.new { |user| user.signup_step <= 2 }</tt>).  The
       #   method, proc or string should return or evaluate to a true or false value.
       def validates_inclusion_of(*attr_names)
-        configuration = attr_names.extract_options!
-
-        enum = configuration[:in] || configuration[:within]
+        options = attr_names.extract_options!
+        options[:in] ||= options.delete(:within)
 
-        raise(ArgumentError, "An object with the method include? is required must be supplied as the :in option of the configuration hash") unless enum.respond_to?(:include?)
+        raise ArgumentError, "An object with the method include? is required must be supplied as the " <<
+                             ":in option of the configuration hash" unless options[:in].respond_to?(:include?)
 
-        validates_each(attr_names, configuration) do |record, attr_name, value|
-          unless enum.include?(value)
-            record.errors.add(attr_name, :inclusion, :default => configuration[:message], :value => value)
-          end
-        end
+        validates_with InclusionValidator, options.merge(:attributes => attr_names)
       end
     end
   end
diff --git a/activemodel/lib/active_model/validations/length.rb b/activemodel/lib/active_model/validations/length.rb
index e91841bd1c..66b2ae5b18 100644
--- a/activemodel/lib/active_model/validations/length.rb
+++ b/activemodel/lib/active_model/validations/length.rb
@@ -1,7 +1,44 @@
 module ActiveModel
   module Validations
+    class LengthValidator < EachValidator
+      MESSAGES = { :is => :wrong_length, :minimum => :too_short, :maximum => :too_long }.freeze
+      CHECKS   = { :is => :==, :minimum => :>=, :maximum => :<= }.freeze
+
+      attr_reader :type
+
+      def initialize(options)
+        @type = options.delete(:type)
+        super
+      end
+
+      def validate_each(record, attribute, value)
+        checks = options.slice(:minimum, :maximum, :is)
+        value  = options[:tokenizer].call(value) if value.kind_of?(String)
+
+        if [:within, :in].include?(type)
+          range = options[type]
+          checks[:minimum], checks[:maximum] = range.begin, range.end
+          checks[:maximum] -= 1 if range.exclude_end?
+        end
+
+        checks.each do |key, check_value|
+          custom_message = options[:message] || options[MESSAGES[key]]
+          validity_check = CHECKS[key]
+
+          valid_value = if key == :maximum
+            value.nil? || value.size.send(validity_check, check_value)
+          else
+            value && value.size.send(validity_check, check_value)
+          end
+
+          record.errors.add(attribute, MESSAGES[key], :default => custom_message, :count => check_value) unless valid_value
+        end
+      end
+    end
+
     module ClassMethods
       ALL_RANGE_OPTIONS = [ :is, :within, :in, :minimum, :maximum ].freeze
+      DEFAULT_TOKENIZER = lambda { |value| value.split(//) }
 
       # Validates that the specified attribute matches the length restrictions supplied. Only one option can be used at a time:
       #
@@ -38,62 +75,32 @@ module ActiveModel
       # * <tt>:tokenizer</tt> - Specifies how to split up the attribute string. (e.g. <tt>:tokenizer => lambda {|str| str.scan(/\w+/)}</tt> to
       #   count words as in above example.)
       #   Defaults to <tt>lambda{ |value| value.split(//) }</tt> which counts individual characters.
-      def validates_length_of(*attrs)
-        # Merge given options with defaults.
-        options = { :tokenizer => lambda {|value| value.split(//)} }
-        options.update(attrs.extract_options!.symbolize_keys)
+      def validates_length_of(*attr_names)
+        options = { :tokenizer => DEFAULT_TOKENIZER }
+        options.update(attr_names.extract_options!)
 
         # Ensure that one and only one range option is specified.
         range_options = ALL_RANGE_OPTIONS & options.keys
         case range_options.size
         when 0
-          raise ArgumentError, 'Range unspecified.  Specify the :within, :maximum, :minimum, or :is option.'
+          raise ArgumentError, 'Range unspecified. Specify the :within, :maximum, :minimum, or :is option.'
         when 1
           # Valid number of options; do nothing.
         else
-          raise ArgumentError, 'Too many range options specified.  Choose only one.'
+          raise ArgumentError, 'Too many range options specified. Choose only one.'
         end
 
-        # Get range option and value.
-        option = range_options.first
-        option_value = options[range_options.first]
-        key = {:is => :wrong_length, :minimum => :too_short, :maximum => :too_long}[option]
-        custom_message = options[:message] || options[key]
+        type  = range_options.first
+        value = options[type]
 
-        case option
+        case type
         when :within, :in
-          raise ArgumentError, ":#{option} must be a Range" unless option_value.is_a?(Range)
-
-          validates_each(attrs, options) do |record, attr, value|
-            value = options[:tokenizer].call(value) if value.kind_of?(String)
-
-            min, max = option_value.begin, option_value.end
-            max = max - 1 if option_value.exclude_end?
-
-            if value.nil? || value.size < min
-              record.errors.add(attr, :too_short, :default => custom_message || options[:too_short], :count => min)
-            elsif value.size > max
-              record.errors.add(attr, :too_long, :default => custom_message || options[:too_long], :count => max)
-            end
-          end
+          raise ArgumentError, ":#{type} must be a Range" unless value.is_a?(Range)
         when :is, :minimum, :maximum
-          raise ArgumentError, ":#{option} must be a nonnegative Integer" unless option_value.is_a?(Integer) and option_value >= 0
-
-          # Declare different validations per option.
-          validity_checks = { :is => "==", :minimum => ">=", :maximum => "<=" }
-
-          validates_each(attrs, options) do |record, attr, value|
-            value = options[:tokenizer].call(value) if value.kind_of?(String)
-
-            valid_value = if option == :maximum
-              value.nil? || value.size.send(validity_checks[option], option_value)
-            else
-              value && value.size.send(validity_checks[option], option_value)
-            end
-
-            record.errors.add(attr, key, :default => custom_message, :count => option_value) unless valid_value
-          end
+          raise ArgumentError, ":#{type} must be a nonnegative Integer" unless value.is_a?(Integer) && value >= 0
         end
+
+        validates_with LengthValidator, options.merge(:attributes => attr_names, :type => type)
       end
 
       alias_method :validates_size_of, :validates_length_of
diff --git a/activemodel/lib/active_model/validations/numericality.rb b/activemodel/lib/active_model/validations/numericality.rb
index 32dbcd82d0..8ffa395a2d 100644
--- a/activemodel/lib/active_model/validations/numericality.rb
+++ b/activemodel/lib/active_model/validations/numericality.rb
@@ -1,9 +1,55 @@
 module ActiveModel
   module Validations
+    class NumericalityValidator < EachValidator
+      CHECKS = { :greater_than => '>', :greater_than_or_equal_to => '>=',
+                 :equal_to => '==', :less_than => '<', :less_than_or_equal_to => '<=',
+                 :odd => 'odd?', :even => 'even?' }.freeze
+
+      def validate_each(record, attr_name, value)
+        before_type_cast = "#{attr_name}_before_type_cast"
+
+        if record.respond_to?(before_type_cast.to_sym)
+          raw_value = record.send("#{attr_name}_before_type_cast") || value
+        else
+          raw_value = value
+        end
+
+        return if options[:allow_nil] and raw_value.nil?
+
+        if options[:only_integer]
+          unless raw_value.to_s =~ /\A[+-]?\d+\Z/
+            record.errors.add(attr_name, :not_a_number, :value => raw_value, :default => options[:message])
+            return
+          end
+          raw_value = raw_value.to_i
+        else
+          begin
+            raw_value = Kernel.Float(raw_value)
+          rescue ArgumentError, TypeError
+            record.errors.add(attr_name, :not_a_number, :value => raw_value, :default => options[:message])
+            return
+          end
+        end
+
+        options.slice(*CHECKS.keys).each do |option, option_value|
+          case option
+          when :odd, :even
+            unless raw_value.to_i.method(CHECKS[option])[]
+              record.errors.add(attr_name, option, :value => raw_value, :default => options[:message])
+            end
+          else
+            option_value = option_value.call(record)        if option_value.is_a? Proc
+            option_value = record.method(option_value).call if option_value.is_a? Symbol
+            
+            unless raw_value.method(CHECKS[option])[option_value]
+              record.errors.add(attr_name, option, :default => options[:message], :value => raw_value, :count => option_value)
+            end
+          end
+        end      
+      end
+    end
     module ClassMethods
-      ALL_NUMERICALITY_CHECKS = { :greater_than => '>', :greater_than_or_equal_to => '>=',
-                                  :equal_to => '==', :less_than => '<', :less_than_or_equal_to => '<=',
-                                  :odd => 'odd?', :even => 'even?' }.freeze
+
 
       # Validates whether the value of the specified attribute is numeric by trying to convert it to
       # a float with Kernel.Float (if <tt>only_integer</tt> is false) or applying it to the regular expression
@@ -44,61 +90,18 @@ module ActiveModel
       #     validates_numericality_of :width, :greater_than => :minimum_weight
       #   end
       #
-      #
-
       def validates_numericality_of(*attr_names)
-        configuration = { :only_integer => false, :allow_nil => false }
-        configuration.update(attr_names.extract_options!)
+        options = { :only_integer => false, :allow_nil => false }
+        options.update(attr_names.extract_options!)
 
-        numericality_options = ALL_NUMERICALITY_CHECKS.keys & configuration.keys
+        numericality_options = NumericalityValidator::CHECKS.keys & options.keys
 
         (numericality_options - [ :odd, :even ]).each do |option|
-          value = configuration[option]
+          value = options[option]
           raise ArgumentError, ":#{option} must be a number, a symbol or a proc" unless value.is_a?(Numeric) || value.is_a?(Proc) || value.is_a?(Symbol)
         end
 
-        validates_each(attr_names,configuration) do |record, attr_name, value|
-          before_type_cast = "#{attr_name}_before_type_cast"
-
-          if record.respond_to?(before_type_cast.to_sym)
-            raw_value = record.send("#{attr_name}_before_type_cast") || value
-          else
-            raw_value = value
-          end
-
-          next if configuration[:allow_nil] and raw_value.nil?
-
-          if configuration[:only_integer]
-            unless raw_value.to_s =~ /\A[+-]?\d+\Z/
-              record.errors.add(attr_name, :not_a_number, :value => raw_value, :default => configuration[:message])
-              next
-            end
-            raw_value = raw_value.to_i
-          else
-            begin
-              raw_value = Kernel.Float(raw_value)
-            rescue ArgumentError, TypeError
-              record.errors.add(attr_name, :not_a_number, :value => raw_value, :default => configuration[:message])
-              next
-            end
-          end
-
-          numericality_options.each do |option|
-            case option
-            when :odd, :even
-              unless raw_value.to_i.method(ALL_NUMERICALITY_CHECKS[option])[]
-                record.errors.add(attr_name, option, :value => raw_value, :default => configuration[:message])
-              end
-            else
-              configuration[option] = configuration[option].call(record)        if configuration[option].is_a? Proc
-              configuration[option] = record.method(configuration[option]).call if configuration[option].is_a? Symbol
-              
-              unless raw_value.method(ALL_NUMERICALITY_CHECKS[option])[configuration[option]]
-                record.errors.add(attr_name, option, :default => configuration[:message], :value => raw_value, :count => configuration[option])
-              end
-            end
-          end
-        end
+        validates_with NumericalityValidator, options.merge(:attributes => attr_names)
       end
     end
   end
diff --git a/activemodel/lib/active_model/validations/presence.rb b/activemodel/lib/active_model/validations/presence.rb
index 3ff677c137..a4c6f866a7 100644
--- a/activemodel/lib/active_model/validations/presence.rb
+++ b/activemodel/lib/active_model/validations/presence.rb
@@ -2,6 +2,12 @@ require 'active_support/core_ext/object/blank'
 
 module ActiveModel
   module Validations
+    class PresenceValidator < EachValidator
+      def validate(record)
+        record.errors.add_on_blank(attributes, options[:message])
+      end
+    end
+
     module ClassMethods
       # Validates that the specified attributes are not blank (as defined by Object#blank?). Happens by default on save. Example:
       #
@@ -28,13 +34,8 @@ module ActiveModel
       #   The method, proc or string should return or evaluate to a true or false value.
       #
       def validates_presence_of(*attr_names)
-        configuration = attr_names.extract_options!
-
-        # can't use validates_each here, because it cannot cope with nonexistent attributes,
-        # while errors.add_on_empty can
-        validate configuration do |record|
-          record.errors.add_on_blank(attr_names, configuration[:message])
-        end
+        options = attr_names.extract_options!
+        validates_with PresenceValidator, options.merge(:attributes => attr_names)
       end
     end
   end
diff --git a/activemodel/lib/active_model/validations/with.rb b/activemodel/lib/active_model/validations/with.rb
index 8313aded11..626e9d5731 100644
--- a/activemodel/lib/active_model/validations/with.rb
+++ b/activemodel/lib/active_model/validations/with.rb
@@ -50,10 +50,7 @@ module ActiveModel
       #
       def validates_with(*args)
         options = args.extract_options!
-
-        args.each do |klass|
-          validate klass.new(options.except(:on, :if, :unless)), options
-        end
+        args.each { |klass| validate(klass.new(options), options) }
       end
     end
   end
diff --git a/activemodel/lib/active_model/validator.rb b/activemodel/lib/active_model/validator.rb
index 80a538fcb6..6885c6800e 100644
--- a/activemodel/lib/active_model/validator.rb
+++ b/activemodel/lib/active_model/validator.rb
@@ -1,5 +1,4 @@
 module ActiveModel #:nodoc:
-
   # A simple base class that can be used along with ActiveModel::Base.validates_with
   #
   #   class Person < ActiveModel::Base
@@ -61,7 +60,28 @@ module ActiveModel #:nodoc:
     end
 
     def validate(record)
-      raise "You must override this method"
+      raise NotImplementedError
+    end
+  end
+
+  class EachValidator < Validator
+    attr_reader :attributes
+
+    def initialize(options)
+      @attributes = options.delete(:attributes)
+      super
+    end
+
+    def validate(record)
+      attributes.each do |attribute|
+        value = record.send(:read_attribute_for_validation, attribute)
+        next if (value.nil? && options[:allow_nil]) || (value.blank? && options[:allow_blank])
+        validate_each(record, attribute, value)
+      end
+    end
+
+    def validate_each(record)
+      raise NotImplementedError
     end
   end
 end
diff --git a/activemodel/test/cases/validations/with_validation_test.rb b/activemodel/test/cases/validations/with_validation_test.rb
index 4350ad69ec..953ff8aa2d 100644
--- a/activemodel/test/cases/validations/with_validation_test.rb
+++ b/activemodel/test/cases/validations/with_validation_test.rb
@@ -98,10 +98,10 @@ class ValidatesWithTest < ActiveRecord::TestCase
     assert topic.errors[:base].include?(ERROR_MESSAGE)
   end
 
-  test "passes all non-standard configuration options to the validator class" do
+  test "passes all configuration options to the validator class" do
     topic = Topic.new
     validator = mock()
-    validator.expects(:new).with({:foo => :bar}).returns(validator)
+    validator.expects(:new).with(:foo => :bar, :if => "1 == 1").returns(validator)
     validator.expects(:validate).with(topic)
 
     Topic.validates_with(validator, :if => "1 == 1", :foo => :bar)