be more generous to implementations that have implemented correctly
diff --git a/Lib/test/test_math.py b/Lib/test/test_math.py
index 3049ef1..680c6ac 100644
--- a/Lib/test/test_math.py
+++ b/Lib/test/test_math.py
@@ -876,8 +876,8 @@
 
         self.assertRaises(TypeError, math.trunc)
         self.assertRaises(TypeError, math.trunc, 1, 2)
-        # XXX: This is not ideal, but see the comment in math_trunc().
-        self.assertRaises(AttributeError, math.trunc, TestNoTrunc())
+        self.assertRaises((AttributeError, TypeError), math.trunc,
+                          TestNoTrunc())
 
         t = TestNoTrunc()
         t.__trunc__ = lambda *args: args