Support Windows 7 with Python 3.8

test_network_monitor.py

@@ -1,6 +1,7 @@
 import pathlib
 import json
 import sys
+import subprocess
 import tempfile
 import threading
 import unittest
@@ -11,6 +12,24 @@ from network_monitor import Detector, analyze_trace, parse_ping, parse_trace, ru
 
 
 class MonitorTests(unittest.TestCase):
+    @unittest.skipUnless(sys.platform == "win32", "requires Windows ping and tracert")
+    def test_main_finishes_diagnostic_and_closes_log(self):
+        # Exercise real executor shutdown on the interpreter running the suite,
+        # including Python 3.8, where cancel_futures is unavailable.
+        with tempfile.TemporaryDirectory() as directory:
+            result = subprocess.run(
+                [sys.executable, str(pathlib.Path(__file__).with_name("network_monitor.py")),
+                 "--target", "127.0.0.1", "--count", "1", "--trace-now",
+                 "--log-dir", directory],
+                stdout=subprocess.PIPE, stderr=subprocess.STDOUT, timeout=20)
+            self.assertEqual(result.returncode, 0, result.stdout.decode(errors="replace"))
+            entries = [json.loads(line) for line in
+                       (pathlib.Path(directory) / "events.jsonl").read_text().splitlines()]
+            self.assertEqual(entries[-1]["event"], "stop")
+            self.assertEqual(entries[-1]["samples"], 1)
+            self.assertTrue(any(entry["event"] == "trace_complete" for entry in entries))
+            self.assertFalse(any(entry["event"] == "error" for entry in entries))
+
     def test_only_bad_pings_are_logged(self):
         with tempfile.TemporaryDirectory() as directory:
             log = Log(pathlib.Path(directory))