Add gdbm test

Author: Erlend E. Aasland

Lib/test/test_dbm_gnu.py

@@ -1,5 +1,5 @@
 from test import support
-from test.support import import_helper
+from test.support import import_helper, cpython_only
 gdbm = import_helper.import_module("dbm.gnu") #skip if not supported
 import unittest
 import os
@@ -27,6 +27,13 @@ def tearDown(self):
             self.g.close()
         unlink(filename)
 
+    @cpython_only
+    def test_uninitialised_new(self):
+        # Prevent heap types from being created uninitialised (bpo-43916)
+        self.g = gdbm.open(filename, 'c')
+        tp = type(self.g)
+        self.assertRaises(TypeError, tp)
+
     def test_key_methods(self):
         self.g = gdbm.open(filename, 'c')
         self.assertEqual(self.g.keys(), [])