1 files changed, 66 insertions, 0 deletions
diff --git a/Lib/test/test_raise.py b/Lib/test/test_raise.py
index 103f608..c1ef154 100644
--- a/Lib/test/test_raise.py
+++ b/Lib/test/test_raise.py
@@ -228,6 +228,72 @@ class TestTraceback(unittest.TestCase):
             self.fail("No exception raised")
 
 
+class TestTracebackType(unittest.TestCase):
+
+    def raiser(self):
+        raise ValueError
+
+    def test_attrs(self):
+        try:
+            self.raiser()
+        except Exception as exc:
+            tb = exc.__traceback__
+
+        self.assertIsInstance(tb.tb_next, types.TracebackType)
+        self.assertIs(tb.tb_frame, sys._getframe())
+        self.assertIsInstance(tb.tb_lasti, int)
+        self.assertIsInstance(tb.tb_lineno, int)
+
+        self.assertIs(tb.tb_next.tb_next, None)
+
+        # Invalid assignments
+        with self.assertRaises(TypeError):
+            del tb.tb_next
+
+        with self.assertRaises(TypeError):
+            tb.tb_next = "asdf"
+
+        # Loops
+        with self.assertRaises(ValueError):
+            tb.tb_next = tb
+
+        with self.assertRaises(ValueError):
+            tb.tb_next.tb_next = tb
+
+        # Valid assignments
+        tb.tb_next = None
+        self.assertIs(tb.tb_next, None)
+
+        new_tb = get_tb()
+        tb.tb_next = new_tb
+        self.assertIs(tb.tb_next, new_tb)
+
+    def test_constructor(self):
+        other_tb = get_tb()
+        frame = sys._getframe()
+
+        tb = types.TracebackType(other_tb, frame, 1, 2)
+        self.assertEqual(tb.tb_next, other_tb)
+        self.assertEqual(tb.tb_frame, frame)
+        self.assertEqual(tb.tb_lasti, 1)
+        self.assertEqual(tb.tb_lineno, 2)
+
+        tb = types.TracebackType(None, frame, 1, 2)
+        self.assertEqual(tb.tb_next, None)
+
+        with self.assertRaises(TypeError):
+            types.TracebackType("no", frame, 1, 2)
+
+        with self.assertRaises(TypeError):
+            types.TracebackType(other_tb, "no", 1, 2)
+
+        with self.assertRaises(TypeError):
+            types.TracebackType(other_tb, frame, "no", 2)
+
+        with self.assertRaises(TypeError):
+            types.TracebackType(other_tb, frame, 1, "nuh-uh")
+
+
 class TestContext(unittest.TestCase):
     def test_instance_context_instance_raise(self):
         context = IndexError()