fixe for attribute write and raw value methods

add new generalised method to get raw value without dependence on
before_type_cast which may not be supported in ORMs

call super to define full ORM write method default

spec/validates_timeliness/attribute_methods_spec.rb

@@ -4,19 +4,35 @@ describe ValidatesTimeliness::AttributeMethods do
   before do
     Employee.validates_datetime :birth_datetime
     Employee.define_attribute_methods
+    Person.validates_datetime :birth_datetime
+    Person.define_attribute_methods [:birth_datetime]
   end
 
-  it 'should define attribute write method for validated attributes' do
-    Employee.instance_methods(false).should include("birth_datetime=")
+  it 'should define _timeliness_raw_value_for instance method' do
+    Person.instance_methods.should include('_timeliness_raw_value_for')
+  end
+  
+  context "attribute write method" do
+    it 'should cache attribute raw value' do
+      r = Employee.new
+      r.birth_datetime = date_string = '2010-01-01'
+      r._timeliness_raw_value_for(:birth_datetime).should == date_string
+    end
   end
 
-  it 'should define attribute before_type_cast method for validated attributes' do
-    Employee.instance_methods(false).should include("birth_datetime_before_type_cast")
-  end
+  context "before_type_cast method" do
+    it 'should be defined on class if ORM supports it' do
+      Employee.instance_methods(false).should include("birth_datetime_before_type_cast")
+    end
 
-  it 'should store original raw value on attribute write' do
-    r = Employee.new
-    r.birth_datetime = '2010-01-01'
-    r.birth_datetime_before_type_cast.should == '2010-01-01'
+    it 'should not be defined if ORM does not support it' do
+      Person.instance_methods(false).should_not include("birth_datetime_before_type_cast")
+    end
+
+    it 'should return original value' do
+      r = Employee.new
+      r.birth_datetime = date_string = '2010-01-01'
+      r.birth_datetime_before_type_cast.should == date_string
+    end
   end
 end