adds test coverage to ensure DateTime#advance processes first the date deltas,...

adds test coverage to ensure DateTime#advance processes first the date deltas, and then the time deltas

activesupport/test/core_ext/date_time_ext_test.rb

@@ -171,22 +171,29 @@ def test_change
   end
 
   def test_advance
-    assert_equal DateTime.civil(2006,2,28,15,15,10), DateTime.civil(2005,2,28,15,15,10).advance(:years => 1)
-    assert_equal DateTime.civil(2005,6,28,15,15,10), DateTime.civil(2005,2,28,15,15,10).advance(:months => 4)
-    assert_equal DateTime.civil(2005,3,21,15,15,10), DateTime.civil(2005,2,28,15,15,10).advance(:weeks => 3)
-    assert_equal DateTime.civil(2005,3,5,15,15,10), DateTime.civil(2005,2,28,15,15,10).advance(:days => 5)
-    assert_equal DateTime.civil(2012,9,28,15,15,10), DateTime.civil(2005,2,28,15,15,10).advance(:years => 7, :months => 7)
-    assert_equal DateTime.civil(2013,10,3,15,15,10), DateTime.civil(2005,2,28,15,15,10).advance(:years => 7, :months => 19, :days => 5)
+    assert_equal DateTime.civil(2006,2,28,15,15,10),  DateTime.civil(2005,2,28,15,15,10).advance(:years => 1)
+    assert_equal DateTime.civil(2005,6,28,15,15,10),  DateTime.civil(2005,2,28,15,15,10).advance(:months => 4)
+    assert_equal DateTime.civil(2005,3,21,15,15,10),  DateTime.civil(2005,2,28,15,15,10).advance(:weeks => 3)
+    assert_equal DateTime.civil(2005,3,5,15,15,10),   DateTime.civil(2005,2,28,15,15,10).advance(:days => 5)
+    assert_equal DateTime.civil(2012,9,28,15,15,10),  DateTime.civil(2005,2,28,15,15,10).advance(:years => 7, :months => 7)
+    assert_equal DateTime.civil(2013,10,3,15,15,10),  DateTime.civil(2005,2,28,15,15,10).advance(:years => 7, :months => 19, :days => 5)
     assert_equal DateTime.civil(2013,10,17,15,15,10), DateTime.civil(2005,2,28,15,15,10).advance(:years => 7, :months => 19, :weeks => 2, :days => 5)
     assert_equal DateTime.civil(2001,12,27,15,15,10), DateTime.civil(2005,2,28,15,15,10).advance(:years => -3, :months => -2, :days => -1)
-    assert_equal DateTime.civil(2005,2,28,15,15,10), DateTime.civil(2004,2,29,15,15,10).advance(:years => 1) #leap day plus one year
-    assert_equal DateTime.civil(2005,2,28,20,15,10), DateTime.civil(2005,2,28,15,15,10).advance(:hours => 5)
-    assert_equal DateTime.civil(2005,2,28,15,22,10), DateTime.civil(2005,2,28,15,15,10).advance(:minutes => 7)
-    assert_equal DateTime.civil(2005,2,28,15,15,19), DateTime.civil(2005,2,28,15,15,10).advance(:seconds => 9)
-    assert_equal DateTime.civil(2005,2,28,20,22,19), DateTime.civil(2005,2,28,15,15,10).advance(:hours => 5, :minutes => 7, :seconds => 9)
-    assert_equal DateTime.civil(2005,2,28,10,8,1), DateTime.civil(2005,2,28,15,15,10).advance(:hours => -5, :minutes => -7, :seconds => -9)
+    assert_equal DateTime.civil(2005,2,28,15,15,10),  DateTime.civil(2004,2,29,15,15,10).advance(:years => 1) #leap day plus one year
+    assert_equal DateTime.civil(2005,2,28,20,15,10),  DateTime.civil(2005,2,28,15,15,10).advance(:hours => 5)
+    assert_equal DateTime.civil(2005,2,28,15,22,10),  DateTime.civil(2005,2,28,15,15,10).advance(:minutes => 7)
+    assert_equal DateTime.civil(2005,2,28,15,15,19),  DateTime.civil(2005,2,28,15,15,10).advance(:seconds => 9)
+    assert_equal DateTime.civil(2005,2,28,20,22,19),  DateTime.civil(2005,2,28,15,15,10).advance(:hours => 5, :minutes => 7, :seconds => 9)
+    assert_equal DateTime.civil(2005,2,28,10,8,1),    DateTime.civil(2005,2,28,15,15,10).advance(:hours => -5, :minutes => -7, :seconds => -9)
     assert_equal DateTime.civil(2013,10,17,20,22,19), DateTime.civil(2005,2,28,15,15,10).advance(:years => 7, :months => 19, :weeks => 2, :days => 5, :hours => 5, :minutes => 7, :seconds => 9)
+  end
 
+  def test_advanced_processes_first_the_date_deltas_and_then_the_time_deltas
+    # If the time deltas were processed first, the following datetimes would be advanced to 2010/04/01 instead.
+    assert_equal DateTime.civil(2010, 3, 29), DateTime.civil(2010, 2, 28, 23, 59, 59).advance(:months => 1, :seconds => 1)
+    assert_equal DateTime.civil(2010, 3, 29), DateTime.civil(2010, 2, 28, 23, 59).advance(:months => 1, :minutes => 1)
+    assert_equal DateTime.civil(2010, 3, 29), DateTime.civil(2010, 2, 28, 23).advance(:months => 1, :hours => 1)
+    assert_equal DateTime.civil(2010, 3, 29), DateTime.civil(2010, 2, 28, 22, 58, 59).advance(:months => 1, :hours => 1, :minutes => 1, :seconds => 1)
   end
 
   def test_next_week