added strict_time_type_cast method to handle casting

refactored to be simler and rely on read_atribute method conversion
rather than use new reader method definer got time (Rails 2.1)

spec/attribute_methods_spec.rb

@@ -33,6 +33,9 @@ describe ValidatesTimeliness::AttributeMethods do
       end
     end
     
+    # This fails running as plugin under vendor using Rails 2.1RC
+    # due to write_attribute_with_dirty ignoring the write method for time zone
+    # method. But invalid dates do return nil when running app.
     it "should return nil when time is invalid" do
       @person.birth_date_and_time = "2000-02-30 01:02:03"
       @person.birth_date_and_time.should be_nil

spec/base_spec.rb

@@ -34,4 +34,38 @@ describe ValidatesTimeliness::Base do
       execute_callstack_for_multiparameter_attributes(callstack)
     end
   end
+  
+  describe "strict_time_type_cast" do
+    it "should return time object for valid time string" do
+      strict_time_type_cast("2000-01-01 12:13:14").should be_kind_of(Time)
+    end
+    
+    it "should return nil for time string with invalid date part" do
+      strict_time_type_cast("2000-02-30 12:13:14").should be_nil
+    end
+    
+    it "should return nil for time string with invalid time part" do
+      strict_time_type_cast("2000-02-01 25:13:14").should be_nil      
+    end
+  end
+  
+  describe "read_attribute" do
+    it "should return time object from time string" do
+      @attributes = {}
+      self.stub!(:column_for_attribute).and_return( mock('Column', :klass => Time) )
+      self.stub!(:unserializable_attribute?).and_return(false)
+      
+      @attributes['birth_date_and_time'] = "1980-01-01 00:00:00"
+      read_attribute(:birth_date_and_time).should be_kind_of(Time)
+    end
+
+    it "should return nil from invalid time string" do
+      @attributes = {}
+      self.stub!(:column_for_attribute).and_return( mock('Column', :klass => Time) )
+      self.stub!(:unserializable_attribute?).and_return(false)
+      
+      @attributes['birth_date_and_time'] = "1980-02-30 00:00:00"
+      read_attribute(:birth_date_and_time).should be_nil
+    end
+  end
 end