Index: Lib/test/test_calendar.py
===================================================================
--- Lib/test/test_calendar.py	(revision 83111)
+++ Lib/test/test_calendar.py	(working copy)
@@ -416,7 +416,24 @@
         with self.assertRaises(calendar.IllegalMonthError):
             calendar.monthrange(2004, 13)
 
+class LeapdaysTestCase(unittest.TestCase):
+    def test_no_range(self):
+        # test when no range i.e. two identical years as args
+        self.assertEqual(calendar.leapdays(2010,2010), 0)
 
+    def test_no_leapdays(self):
+        # test when no leap years in range
+        self.assertEqual(calendar.leapdays(2010,2011), 0)
+
+    def test_no_leapdays_upper_boundary(self):
+        # test no leap years in range, when upper boundary is a leap year
+        self.assertEqual(calendar.leapdays(2010,2012), 0)
+
+    def test_one_leapday_lower_boundary(self):
+        # test when one leap year in range, lower boundary is leap year
+        self.assertEqual(calendar.leapdays(2012,2013), 1)
+
+
 def test_main():
     support.run_unittest(
         OutputTestCase,
@@ -425,6 +442,7 @@
         SundayTestCase,
         TimegmTestCase,
         MonthRangeTestCase,
+        LeapdaysTestCase,
     )