1 files changed, 27 insertions, 3 deletions
diff --git a/activemodel/test/cases/dirty_test.rb b/activemodel/test/cases/dirty_test.rb
index ba45089cca..54427a1513 100644
--- a/activemodel/test/cases/dirty_test.rb
+++ b/activemodel/test/cases/dirty_test.rb
@@ -3,11 +3,12 @@ require "cases/helper"
 class DirtyTest < ActiveModel::TestCase
   class DirtyModel
     include ActiveModel::Dirty
-    define_attribute_methods :name, :color
+    define_attribute_methods :name, :color, :size
 
     def initialize
       @name = nil
       @color = nil
+      @size = nil
     end
 
     def name
@@ -28,9 +29,17 @@ class DirtyTest < ActiveModel::TestCase
       @color = val
     end
 
+    def size
+      @size
+    end
+
+    def size=(val)
+      attribute_will_change!(:size) unless val == @size
+      @size = val
+    end
+
     def save
-      @previously_changed = changes
-      @changed_attributes.clear
+      changes_applied
     end
   end
 
@@ -58,6 +67,16 @@ class DirtyTest < ActiveModel::TestCase
     assert_equal [nil, "John"], @model.changes['name']
   end
 
+  test "checking if an attribute has changed to a particular value" do
+    @model.name = "Ringo"
+    assert @model.name_changed?(from: nil, to: "Ringo")
+    assert_not @model.name_changed?(from: "Pete", to: "Ringo")
+    assert @model.name_changed?(to: "Ringo")
+    assert_not @model.name_changed?(to: "Pete")
+    assert @model.name_changed?(from: nil)
+    assert_not @model.name_changed?(from: "Pete")
+  end
+
   test "changes accessible through both strings and symbols" do
     @model.name = "David"
     assert_not_nil @model.changes[:name]
@@ -125,4 +144,9 @@ class DirtyTest < ActiveModel::TestCase
     assert_equal ["Otto", "Mr. Manfredgensonton"], @model.name_change
     assert_equal @model.name_was, "Otto"
   end
+
+  test "using attribute_will_change! with a symbol" do
+    @model.size = 1
+    assert @model.size_changed?
+  end
 end