1 files changed, 57 insertions, 5 deletions
diff --git a/activesupport/test/callbacks_test.rb b/activesupport/test/callbacks_test.rb
index 8810302f40..13f2e3cdaf 100644
--- a/activesupport/test/callbacks_test.rb
+++ b/activesupport/test/callbacks_test.rb
@@ -297,7 +297,7 @@ module CallbacksTest
       end
     end
   end
-  
+
   class AroundPersonResult < MySuper
     attr_reader :result
 
@@ -308,7 +308,7 @@ module CallbacksTest
     def tweedle_dum
       @result = yield
     end
-    
+
     def tweedle_1
       :tweedle_1
     end
@@ -316,7 +316,7 @@ module CallbacksTest
     def tweedle_2
       :tweedle_2
     end
-    
+
     def save
       run_callbacks :save do
         :running
@@ -410,7 +410,7 @@ module CallbacksTest
       ], around.history
     end
   end
-  
+
   class AroundCallbackResultTest < ActiveSupport::TestCase
     def test_save_around
       around = AroundPersonResult.new
@@ -607,6 +607,45 @@ module CallbacksTest
     end
   end
 
+  class OneTwoThreeSave
+    include ActiveSupport::Callbacks
+
+    define_callbacks :save
+
+    attr_accessor :record
+
+    def initialize
+      @record = []
+    end
+
+    def save
+      run_callbacks :save do
+        @record << "yielded"
+      end
+    end
+
+    def first
+      @record << "one"
+    end
+
+    def second
+      @record << "two"
+    end
+
+    def third
+      @record << "three"
+    end
+  end
+
+  class DuplicatingCallbacks < OneTwoThreeSave
+    set_callback :save, :before, :first, :second
+    set_callback :save, :before, :first, :third
+  end
+
+  class DuplicatingCallbacksInSameCall < OneTwoThreeSave
+    set_callback :save, :before, :first, :second, :first, :third
+  end
+
   class UsingObjectTest < ActiveSupport::TestCase
     def test_before_object
       u = UsingObjectBefore.new
@@ -709,5 +748,18 @@ module CallbacksTest
       end
     end
   end
- 
+
+  class ExcludingDuplicatesCallbackTest < ActiveSupport::TestCase
+    def test_excludes_duplicates_in_separate_calls
+      model = DuplicatingCallbacks.new
+      model.save
+      assert_equal ["two", "one", "three", "yielded"], model.record
+    end
+
+    def test_excludes_duplicates_in_one_call
+      model = DuplicatingCallbacksInSameCall.new
+      model.save
+      assert_equal ["two", "one", "three", "yielded"], model.record
+    end
+  end
 end