Add expectedFailure to test_warnings

Lib/unittest/test/test_runner.py

@@ -1137,6 +1137,8 @@ class Test_TextTestRunner(unittest.TestCase):
         expectedresult = (runner.stream, DESCRIPTIONS, VERBOSITY)
         self.assertEqual(runner._makeResult(), expectedresult)
 
+    # TODO: RUSTPYTHON
+    @unittest.expectedFailure
     def test_warnings(self):
         """
         Check that warnings argument of TextTestRunner correctly affects the