test(#838): bound adapter failure proof

packages/mosaic/src/mutator-gate/runtime_tools_unittest.py

@@ -254,13 +254,21 @@ class ExecutableEntrypointTest(unittest.TestCase):
                         "MOSAIC_LEASE_SESSION_ID": "d" * 64,
                         "MOSAIC_RUNTIME_GENERATION": "1",
                     }
-                    result = subprocess.run(
-                        [sys.executable, str(TOOLS_DIR / "mutator-gate.py"), "--runtime", runtime],
-                        input=b'{"tool_name":"Read"}\n',
-                        capture_output=True,
-                        env=environment,
-                        check=False,
-                    )
+                    try:
+                        result = subprocess.run(
+                            [sys.executable, str(TOOLS_DIR / "mutator-gate.py"), "--runtime", runtime],
+                            input=b'{"tool_name":"Read"}\n',
+                            capture_output=True,
+                            env=environment,
+                            check=False,
+                            timeout=5,
+                        )
+                    except subprocess.TimeoutExpired as exc:
+                        server.close()
+                        thread.join(timeout=2)
+                        self.fail(
+                            f"{runtime} gate hung on wire reply {wire_reply!r}: {exc}"
+                        )
                     thread.join(timeout=2)
 
                     self.assertFalse(thread.is_alive())