Fix validates_confirmation_of matcher so that it works under Rails 4

Rails 4 changed how validates_confirmation_of works so that the error
message is applied to the confirmation attribute, not the original
attribute.

lib/shoulda/matchers/active_model/allow_value_matcher.rb

@@ -30,6 +30,7 @@ module Shoulda # :nodoc:
       class AllowValueMatcher # :nodoc:
         include Helpers
 
+        attr_accessor :attribute_with_message
         attr_accessor :options
 
         def initialize(*values)
@@ -39,7 +40,8 @@ module Shoulda # :nodoc:
         end
 
         def for(attribute)
-          self.attribute = attribute
+          self.attribute_to_set = attribute
+          self.attribute_to_check_message_against = attribute
           self
         end
 
@@ -48,8 +50,11 @@ module Shoulda # :nodoc:
           self
         end
 
-        def with_message(message)
+        def with_message(message, options={})
           self.options[:expected_message] = message
+          if options.key?(:against)
+            self.attribute_to_check_message_against = options[:against]
+          end
           self
         end
 
@@ -63,7 +68,7 @@ module Shoulda # :nodoc:
 
           values_to_match.none? do |value|
             self.value = value
-            instance.send("#{attribute}=", value)
+            instance.send("#{attribute_to_set}=", value)
             errors_match?
           end
         end
@@ -83,7 +88,8 @@ module Shoulda # :nodoc:
         private
 
         attr_accessor :values_to_match, :message_finder_factory,
-          :instance, :attribute, :context, :value, :matched_error
+          :instance, :attribute_to_set, :attribute_to_check_message_against,
+          :context, :value, :matched_error
 
         def errors_match?
           has_messages? && errors_for_attribute_match?
@@ -119,7 +125,7 @@ module Shoulda # :nodoc:
 
         def expectation
           includes_expected_message = expected_message ? "to include #{expected_message.inspect}" : ''
-          [error_source, includes_expected_message, "when #{attribute} is set to #{value.inspect}"].join(' ')
+          [error_source, includes_expected_message, "when #{attribute_to_set} is set to #{value.inspect}"].join(' ')
         end
 
         def error_source
@@ -157,7 +163,7 @@ module Shoulda # :nodoc:
             options[:expected_message],
             :model_name => model_name,
             :instance => instance,
-            :attribute => attribute
+            :attribute => attribute_to_set
           )
         end
 
@@ -166,7 +172,7 @@ module Shoulda # :nodoc:
         end
 
         def message_finder
-          message_finder_factory.new(instance, attribute, context)
+          message_finder_factory.new(instance, attribute_to_check_message_against, context)
         end
       end
     end

lib/shoulda/matchers/active_model/disallow_value_matcher.rb

@@ -20,8 +20,8 @@ module Shoulda # :nodoc:
           self
         end
 
-        def with_message(message)
-          @allow_matcher.with_message(message)
+        def with_message(message, options={})
+          @allow_matcher.with_message(message, options)
           self
         end
 

lib/shoulda/matchers/active_model/validate_confirmation_of_matcher.rb

@@ -13,9 +13,11 @@ module Shoulda # :nodoc:
       class ValidateConfirmationOfMatcher < ValidationMatcher # :nodoc:
         include Helpers
 
+        attr_reader :attribute, :confirmation_attribute
+
         def initialize(attribute)
           @attribute = attribute
-          @confirmation = "#{attribute}_confirmation"
+          @confirmation_attribute = "#{attribute}_confirmation"
         end
 
         def with_message(message)
@@ -24,7 +26,7 @@ module Shoulda # :nodoc:
         end
 
         def description
-          "require #{@confirmation} to match #{@attribute}"
+          "require #{@confirmation_attribute} to match #{@attribute}"
         end
 
         def matches?(subject)
@@ -40,25 +42,35 @@ module Shoulda # :nodoc:
 
         def disallows_different_value
           set_confirmation('some value')
-          disallows_value_of('different value', @message)
+          disallows_value_of('different value') do |matcher|
+            matcher.with_message(@message, against: error_attribute)
+          end
         end
 
         def allows_same_value
           set_confirmation('same value')
-          allows_value_of('same value', @message)
+          allows_value_of('same value') do |matcher|
+            matcher.with_message(@message, against: error_attribute)
+          end
         end
 
         def allows_missing_confirmation
           set_confirmation(nil)
-          allows_value_of('any value', @message)
+          allows_value_of('any value') do |matcher|
+            matcher.with_message(@message, against: error_attribute)
+          end
         end
 
         def set_confirmation(val)
-          setter = :"#{@confirmation}="
+          setter = :"#{@confirmation_attribute}="
           if @subject.respond_to?(setter)
             @subject.send(setter, val)
           end
         end
+
+        def error_attribute
+          RailsShim.validates_confirmation_of_error_attribute(self)
+        end
       end
     end
   end

lib/shoulda/matchers/active_model/validation_matcher.rb

@@ -30,8 +30,9 @@ module Shoulda # :nodoc:
 
         private
 
-        def allows_value_of(value, message = nil)
+        def allows_value_of(value, message = nil, &block)
           allow = allow_value_matcher(value, message)
+          yield allow if block_given?
 
           if allow.matches?(@subject)
             @failure_message_for_should_not = allow.failure_message_for_should_not
@@ -42,8 +43,9 @@ module Shoulda # :nodoc:
           end
         end
 
-        def disallows_value_of(value, message = nil)
+        def disallows_value_of(value, message = nil, &block)
           disallow = disallow_value_matcher(value, message)
+          yield disallow if block_given?
 
           if disallow.matches?(@subject)
             @failure_message_for_should_not = disallow.failure_message_for_should_not

lib/shoulda/matchers/rails_shim.rb

@@ -25,6 +25,14 @@ module Shoulda # :nodoc:
         end
       end
 
+      def self.validates_confirmation_of_error_attribute(matcher)
+        if rails_major_version == 4
+          matcher.confirmation_attribute
+        else
+          matcher.attribute
+        end
+      end
+
       def self.rails_major_version
         Rails::VERSION::MAJOR
       end

spec/shoulda/matchers/active_model/allow_value_matcher_spec.rb

@@ -56,6 +56,30 @@ describe Shoulda::Matchers::ActiveModel::AllowValueMatcher do
     end
   end
 
+  context 'an attribute where the message occurs on another attribute' do
+    it 'allows a good value' do
+      record_with_custom_validation.should \
+        allow_value('good value').for(:attr).with_message(/some message/, :against => :attr2)
+    end
+
+    it 'rejects a bad value' do
+      record_with_custom_validation.should_not \
+        allow_value('bad value').for(:attr).with_message(/some message/, :against => :attr2)
+    end
+
+    def record_with_custom_validation
+      define_model :example, :attr => :string, :attr2 => :string do
+        validate :custom_validation
+
+        def custom_validation
+          if self[:attr] != 'good value'
+            self.errors[:attr2] << 'some message'
+          end
+        end
+      end.new
+    end
+  end
+
   context "an attribute with a context-dependent validation" do
     context "without the validation context" do
       it "allows a bad value" do

spec/shoulda/matchers/active_model/disallow_value_matcher_spec.rb

@@ -55,6 +55,30 @@ describe Shoulda::Matchers::ActiveModel::DisallowValueMatcher do
     end
   end
 
+  context 'an attribute where the message occurs on another attribute' do
+    it 'matches if the message is correct but the value is not' do
+      record_with_custom_validation.should \
+        matcher('bad value').for(:attr).with_message(/some message/, :against => :attr2)
+    end
+
+    it 'does not match if the value and message are both correct' do
+      record_with_custom_validation.should_not \
+        matcher('good value').for(:attr).with_message(/some message/, :against => :attr2)
+    end
+
+    def record_with_custom_validation
+      define_model :example, :attr => :string, :attr2 => :string do
+        validate :custom_validation
+
+        def custom_validation
+          if self[:attr] != 'good value'
+            self.errors[:attr2] << 'some message'
+          end
+        end
+      end.new
+    end
+  end
+
   def matcher(value)
     described_class.new(value)
   end