diff -r c59d81b802f8 Lib/idlelib/idle_test/test_calltips.py
--- a/Lib/idlelib/idle_test/test_calltips.py	Tue Mar 31 16:35:35 2015 +0200
+++ b/Lib/idlelib/idle_test/test_calltips.py	Tue Mar 31 18:23:00 2015 +0300
@@ -52,7 +52,8 @@ class Get_signatureTest(unittest.TestCas
         def gtest(obj, out):
             self.assertEqual(signature(obj), out)
 
-        gtest(List, List.__doc__)
+        if List.__doc__ is not None:
+            gtest(List, List.__doc__)
         gtest(list.__new__,
                'Create and return a new object.  See help(type) for accurate signature.')
         gtest(list.__init__,
@@ -108,20 +109,23 @@ bytes() -> empty bytes object''')
         def t5(a, b=None, *args, **kw): 'doc'
         t5.tip = "(a, b=None, *args, **kw)"
 
+        doc = '\ndoc' if t1.__doc__ is not None else ''
         for func in (t1, t2, t3, t4, t5, TC):
-            self.assertEqual(signature(func), func.tip + '\ndoc')
+            self.assertEqual(signature(func), func.tip + doc)
 
     def test_methods(self):
+        doc = '\ndoc' if TC.__doc__ is not None else ''
         for meth in (TC.t1, TC.t2, TC.t3, TC.t4, TC.t5, TC.t6, TC.__call__):
-            self.assertEqual(signature(meth), meth.tip + "\ndoc")
-        self.assertEqual(signature(TC.cm), "(a)\ndoc")
-        self.assertEqual(signature(TC.sm), "(b)\ndoc")
+            self.assertEqual(signature(meth), meth.tip + doc)
+        self.assertEqual(signature(TC.cm), "(a)" + doc)
+        self.assertEqual(signature(TC.sm), "(b)" + doc)
 
     def test_bound_methods(self):
         # test that first parameter is correctly removed from argspec
+        doc = '\ndoc' if TC.__doc__ is not None else ''
         for meth, mtip  in ((tc.t1, "()"), (tc.t4, "(*args)"), (tc.t6, "(self)"),
                             (tc.__call__, '(ci)'), (tc, '(ci)'), (TC.cm, "(a)"),):
-            self.assertEqual(signature(meth), mtip + "\ndoc")
+            self.assertEqual(signature(meth), mtip + doc)
 
     def test_starred_parameter(self):
         # test that starred first parameter is *not* removed from argspec