3 files changed, 15 insertions, 3 deletions
diff --git a/activemodel/lib/active_model/validations/length.rb b/activemodel/lib/active_model/validations/length.rb
index 7af6c83460..72735cfb89 100644
--- a/activemodel/lib/active_model/validations/length.rb
+++ b/activemodel/lib/active_model/validations/length.rb
@@ -43,7 +43,8 @@ module ActiveModel
 
           value ||= [] if key == :maximum
 
-          next if value && value.size.send(validity_check, check_value)
+          value_length = value.respond_to?(:length) ? value.length : value.to_s.length
+          next if value_length.send(validity_check, check_value)
 
           errors_options = options.except(*RESERVED_OPTIONS)
           errors_options[:count] = check_value
diff --git a/activemodel/lib/active_model/validator.rb b/activemodel/lib/active_model/validator.rb
index 1c6123eb09..c5ed8d22d3 100644
--- a/activemodel/lib/active_model/validator.rb
+++ b/activemodel/lib/active_model/validator.rb
@@ -120,7 +120,7 @@ module ActiveModel #:nodoc:
     # Override this method in subclasses with validation logic, adding errors
     # to the records +errors+ array where necessary.
     def validate(record)
-      raise NotImplementedError
+      raise NotImplementedError, "Subclasses must implement a validate(record) method."
     end
   end
 
@@ -156,7 +156,7 @@ module ActiveModel #:nodoc:
     # Override this method in subclasses with the validation logic, adding
     # errors to the records +errors+ array where necessary.
     def validate_each(record, attribute, value)
-      raise NotImplementedError
+      raise NotImplementedError, "Subclasses must implement a validate_each(record, attribute, value) method"
     end
 
     # Hook method that gets called by the initializer allowing verification
diff --git a/activemodel/test/cases/validations/length_validation_test.rb b/activemodel/test/cases/validations/length_validation_test.rb
index 1e6180a938..f02514639b 100644
--- a/activemodel/test/cases/validations/length_validation_test.rb
+++ b/activemodel/test/cases/validations/length_validation_test.rb
@@ -342,6 +342,17 @@ class LengthValidationTest < ActiveModel::TestCase
     assert_equal ["Your essay must be at least 5 words."], t.errors[:content]
   end
 
+  def test_validates_length_of_for_fixnum
+    Topic.validates_length_of(:approved, :is => 4)
+
+    t = Topic.new("title" => "uhohuhoh", "content" => "whatever", :approved => 1)
+    assert t.invalid?
+    assert t.errors[:approved].any?
+
+    t = Topic.new("title" => "uhohuhoh", "content" => "whatever", :approved => 1234)
+    assert t.valid?
+  end
+
   def test_validates_length_of_for_ruby_class
     Person.validates_length_of :karma, :minimum => 5