Implement attribute_changed_in_place? for dirty tracking

Ref: remi#383
Closes: remi#382

Override ActiveModel::Dirty's attribute_changed_in_place? to use
Her's change tracking, enabling validates_numericality_of and other
validators that depend on in-place change detection.

Author: voltechs

lib/her/model.rb

@@ -44,6 +44,12 @@ module Model
     include ActiveModel::Conversion
     include ActiveModel::Dirty
 
+    # Override ActiveModel::Dirty's attribute_changed_in_place? to use
+    # Her's change tracking. This allows validates_numericality_of to work.
+    def attribute_changed_in_place?(attribute_name)
+      !changes[attribute_name.to_s].nil?
+    end
+
     # Class methods
     included do
       # Assign the default API

spec/model/attributes_spec.rb

@@ -74,6 +74,12 @@
       expect(@new_user.get_attribute(:unknown_method_for_a_user)).to be_nil
       expect(@new_user.get_attribute(:'life-span')).to eq("3 years")
     end
+
+    it "handles attribute_changed_in_place?" do
+      @new_user = Foo::User.new
+      @new_user.fullname = "Schmoo"
+      expect(@new_user.attribute_changed_in_place?(:fullname)).to be_truthy
+    end
   end
 
   context "assigning new resource data" do

spec/model/validations_spec.rb

@@ -6,9 +6,10 @@
   context "validating attributes" do
     before do
       spawn_model "Foo::User" do
-        attributes :fullname, :email
+        attributes :fullname, :email, :age
         validates_presence_of :fullname
         validates_presence_of :email
+        validates_numericality_of :age
       end
     end
 
@@ -19,6 +20,7 @@
       expect(user.errors.full_messages).to include("Email can't be blank")
       user.fullname = "Tobias Fünke"
       user.email = "tobias@bluthcompany.com"
+      user.age = 35
       expect(user).to be_valid
     end
   end