Fix Riot session aborts, CDN downloads and hidden client recovery

tests/test_urlsession_runner.py

@@ -0,0 +1,55 @@
+"""Check fixture traffic and private-prefix cleanup with a fake darling executable."""
+import json
+import os
+from pathlib import Path
+import stat
+import subprocess
+import sys
+import tempfile
+import unittest
+
+ROOT = Path(__file__).resolve().parents[1]
+
+
+class URLSessionRunnerTests(unittest.TestCase):
+    def test_fixture_and_shutdown_use_only_a_private_prefix(self):
+        with tempfile.TemporaryDirectory() as folder:
+            root = Path(folder)
+            executable = root / 'darling'
+            trace = root / 'trace.jsonl'
+            executable.write_text(f'#!{sys.executable}\n' + f'TRACE = {str(trace)!r}\n' + '''
+import json, os, sys, urllib.request
+with open(TRACE, 'a') as stream:
+    stream.write(json.dumps({'args':sys.argv[1:], 'prefix':os.environ['DPREFIX']}) + '\\n')
+if sys.argv[1] == 'shutdown':
+    raise SystemExit(0)
+assert urllib.request.urlopen(sys.argv[2]).read() == b'darling-session-ok'
+try:
+    urllib.request.urlopen(sys.argv[3], timeout=2)
+except OSError:
+    pass
+else:
+    raise AssertionError('reserved error endpoint unexpectedly accepted a connection')
+print('LIFECYCLE_PASS: fixture')
+print('URLSESSION_PASS: fixture')
+''')
+            executable.chmod(0o755)
+            probe = root / 'probe'
+            probe.write_text('fake probe; never executed')
+            log = root / 'probe.log'
+            result = subprocess.run([sys.executable, str(ROOT / 'tools/riot-urlsession-check.py'),
+                                     '--probe', str(probe), '--log', str(log)],
+                                    env=dict(os.environ, PATH=str(root) + os.pathsep + os.environ['PATH']),
+                                    capture_output=True, text=True, timeout=15)
+            self.assertEqual(result.returncode, 0, result.stdout + result.stderr)
+            calls = [json.loads(line) for line in trace.read_text().splitlines()]
+            self.assertEqual(len(calls), 2)
+            self.assertEqual(calls[1]['args'], ['shutdown'])
+            self.assertEqual(calls[0]['prefix'], calls[1]['prefix'])
+            self.assertNotEqual(Path(calls[0]['prefix']), Path.home() / '.darling')
+            self.assertFalse(Path(calls[0]['prefix']).exists())
+            self.assertEqual(stat.S_IMODE(log.stat().st_mode), 0o600)
+
+
+if __name__ == '__main__':
+    unittest.main()