Fix Time#years_ago and #years_since from leap days. Closes #9865.

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@7867 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

activesupport/CHANGELOG

 *SVN*
 
+* Fix Time#years_ago and #years_since from leap days.  #9865 [Geoff Buesing]
+
 * Time and DateTime#advance accept :hours, :minutes, and :seconds options.  #9825 [Geoff Buesing]
 
 * Fix Date#years_ago and #years_since from leap days.  #9864 [Geoff Buesing]

activesupport/lib/active_support/core_ext/time/calculations.rb

@@ -110,12 +110,12 @@ def months_since(months)
 
         # Returns a new Time representing the time a number of specified years ago
         def years_ago(years)
-          change(:year => self.year - years)
+          advance(:years => -years)
         end
 
         # Returns a new Time representing the time a number of specified years in the future
         def years_since(years)
-          change(:year => self.year + years)
+          advance(:years => years)
         end
 
         # Short-hand for years_ago(1)

activesupport/test/core_ext/time_ext_test.rb

@@ -119,11 +119,13 @@ def test_months_since
   def test_years_ago
     assert_equal Time.local(2004,6,5,10),  Time.local(2005,6,5,10,0,0).years_ago(1)
     assert_equal Time.local(1998,6,5,10), Time.local(2005,6,5,10,0,0).years_ago(7)
+    assert_equal Time.local(2003,2,28,10), Time.local(2004,2,29,10,0,0).years_ago(1) # 1 year ago from leap day
   end
 
   def test_years_since
     assert_equal Time.local(2006,6,5,10),  Time.local(2005,6,5,10,0,0).years_since(1)
     assert_equal Time.local(2012,6,5,10),  Time.local(2005,6,5,10,0,0).years_since(7)
+    assert_equal Time.local(2005,2,28,10), Time.local(2004,2,29,10,0,0).years_since(1) # 1 year since leap day
     # Failure because of size limitations of numeric?
     # assert_equal Time.local(2182,6,5,10),  Time.local(2005,6,5,10,0,0).years_since(177)
   end