1 files changed, 31 insertions, 16 deletions
diff --git a/activesupport/test/test_test.rb b/activesupport/test/test_test.rb
index 63a44e9379..d8a02b5497 100644
--- a/activesupport/test/test_test.rb
+++ b/activesupport/test/test_test.rb
@@ -3,32 +3,47 @@ require File.dirname(__FILE__) + '/abstract_unit'
 class AssertDifferenceTest < Test::Unit::TestCase
   
   def setup
-    @object = Class.new { attr_accessor :num }.new    
+    @object = Class.new do
+      attr_accessor :num 
+      def increment
+        self.num += 1
+      end
+
+      def decrement
+        self.num -= 1
+      end
+    end.new    
+    @object.num = 0
   end
   
   def test_assert_no_difference
-    @object.num = 0
-    
-    assert_no_difference @object, :num do
+    assert_no_difference '@object.num' do
       # ...
     end
-      
   end
+
   def test_assert_difference
-    @object.num = 0
-    
-    
-    assert_difference @object, :num, +1 do
-      @object.num = 1
+    assert_difference '@object.num', +1 do
+      @object.increment
     end
-      
   end
 
-  def test_methods_available
-    
-    assert self.respond_to?(:assert_difference)
-    assert self.respond_to?(:assert_no_difference)
-    
+  def test_assert_difference_with_implicit_difference
+    assert_difference '@object.num' do
+      @object.increment
+    end
   end
 
+  def test_arbitrary_expression
+    assert_difference '@object.num + 1', +2 do
+      @object.increment
+      @object.increment
+    end
+  end
+
+  def test_negative_differences
+    assert_difference '@object.num', -1 do
+      @object.decrement
+    end
+  end
 end