Issue #7819: Check sys.call_tracing() arguments types.

py3k was already patched by issue #3661.
diff --git a/Lib/test/test_sys.py b/Lib/test/test_sys.py
index f58d900..6b45d12 100644
--- a/Lib/test/test_sys.py
+++ b/Lib/test/test_sys.py
@@ -433,6 +433,10 @@
         out = p.communicate()[0].strip()
         self.assertEqual(out, '?')
 
+    def test_call_tracing(self):
+        self.assertEqual(sys.call_tracing(str, (2,)), "2")
+        self.assertRaises(TypeError, sys.call_tracing, str, 2)
+
 
 class SizeofTest(unittest.TestCase):