[electrum] better handle timeouts in test_interface

Summary:
Tests are failing on CI because we don't catch the correct error for python < 3.10

badssl.com  seems to be unresponsive, lately. If this keeps happening, this test should be removed to not slow down the test suite unnecessarily.

Test Plan: `python -m electrumabc.tests.test_interface`

Reviewers: #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Differential Revision: https://reviews.bitcoinabc.org/D14619

electrumabc/tests/test_interface.py

@@ -1,3 +1,4 @@
+import socket
 import ssl
 import unittest
 
@@ -18,8 +19,14 @@ def has_ca_signed_valid_cert(self, server: str) -> bool:
                 else:
                     self.skipTest("This test requires an internet connection.")
                 return bool(s)
-            except TimeoutError:
+            except (TimeoutError, socket.timeout):
+                # In Python >= 3.10, socket.timeout is an alias for TimeoutError.
+                # For lower versions of python we need to catch both.
+                # socket.timeout is deprecated, so when support for Python 3.9 is
+                # dropped it should be removed.
                 retries += 1
+        # if we are here, it means the request keeps timing out
+        self.skipTest(f"Skipping test after 5 timeouts. {server} must be down.")
 
     def test_verify_good_ca_cert(self):
         # These are also a wildcard certificate