Chore: Improve stability of probe_tcp_connect test cases

Author: amotl

pyproject.toml

@@ -77,6 +77,7 @@ optional-dependencies.test = [
   "coverage<8",
   "pytest<9",
   "pytest-fixture-order<1",
+  "pytest-httpserver<2",
   "pytest-ordering<1",
 ]
 urls.changelog = "https://github.com/mqtt-tools/pytest-mqtt/blob/main/CHANGES.rst"

testing/test_util.py

@@ -1,9 +1,9 @@
 from pytest_mqtt.util import probe_tcp_connect
 
 
-def test_probe_tcp_connect_available():
-    assert probe_tcp_connect("9.9.9.9", 443) is True
+def test_probe_tcp_connect_available(httpserver):
+    assert probe_tcp_connect(httpserver.host, httpserver.port) is True
 
 
 def test_probe_tcp_connect_unavailable():
-    assert probe_tcp_connect("9.9.9.9", 444) is False
+    assert probe_tcp_connect("localhost", 12345) is False