Fix dirty handling of nullable non-integer numeric columns [#1692 state:resolved]

Signed-off-by: Frederick Cheung <frederick.cheung@gmail.com>

activerecord/test/cases/dirty_test.rb

@@ -21,6 +21,10 @@ private
   end
 end
 
+class NumericData < ActiveRecord::Base
+  self.table_name = 'numeric_data'
+end
+
 class DirtyTest < ActiveRecord::TestCase
   def test_attribute_changes
     # New record - no changes.
@@ -68,6 +72,26 @@ class DirtyTest < ActiveRecord::TestCase
     end
   end
 
+  def test_nullable_decimal_not_marked_as_changed_if_new_value_is_blank
+    numeric_data = NumericData.new
+
+    ["", nil].each do |value|
+      numeric_data.bank_balance = value
+      assert !numeric_data.bank_balance_changed?
+      assert_nil numeric_data.bank_balance_change
+    end
+  end
+
+  def test_nullable_float_not_marked_as_changed_if_new_value_is_blank
+    numeric_data = NumericData.new
+
+    ["", nil].each do |value|
+      numeric_data.temperature = value
+      assert !numeric_data.temperature_changed?
+      assert_nil numeric_data.temperature_change
+    end
+  end
+
   def test_nullable_integer_zero_to_string_zero_not_marked_as_changed
     pirate = Pirate.new
     pirate.parrot_id = 0

activerecord/test/schema/schema.rb

@@ -252,6 +252,7 @@ ActiveRecord::Schema.define do
     t.decimal :world_population, :precision => 10, :scale => 0
     t.decimal :my_house_population, :precision => 2, :scale => 0
     t.decimal :decimal_number_with_default, :precision => 3, :scale => 2, :default => 2.78
+    t.float   :temperature
   end
 
   create_table :orders, :force => true do |t|