Add a wrapper to test existing Udp_server test code.

tests/test_Udp_server.py

@@ -0,0 +1,17 @@
+import unittest
+from sippy.Udp_server import self_test
+
+class TestSelfTest(unittest.TestCase):
+    def test_run(self):
+        # Create an instance of the self_test class
+        test_instance = self_test()
+
+        # Run the existing logic
+        test_instance.run()
+
+        # You can add assertions here if needed to check the final state or outcomes.
+        # For example, you might want to check if npongs reached 0.
+        self.assertEqual(test_instance.npongs, 0)
+
+if __name__ == '__main__':
+    unittest.main()