Add negative test

Author: edvilme

Lib/test/test_pyrepl/test_utils.py

@@ -50,6 +50,9 @@ def test_wlen(self):
     def test_wlen_with_osc_sequence(self):
         self.assertEqual(wlen("\x1b]633;A\x07>>> "), 4)
 
+    def test_wlen_with_unterminated_osc_sequence(self):
+        self.assertEqual(wlen("\x1b]633;A"), 7)
+
     def test_prev_next_window(self):
         def gen_normal():
             yield 1