feat: serialize public hardware execution

tests/unit/test_hardware_execution_coordinator.py

@@ -0,0 +1,42 @@
+from __future__ import annotations
+
+import threading
+import unittest
+
+from cognitive_agent.infrastructure.can.hardware import (
+    HardwareBusyError,
+    HardwareExecutionCoordinator,
+)
+
+
+class HardwareExecutionCoordinatorTests(unittest.TestCase):
+    def test_rejects_overlapping_owner_and_releases_after_completion(self) -> None:
+        coordinator = HardwareExecutionCoordinator(retry_after_seconds=7)
+        entered = threading.Event()
+        release = threading.Event()
+
+        def hold_bench() -> None:
+            with coordinator.reserve():
+                entered.set()
+                self.assertTrue(release.wait(timeout=3))
+
+        owner = threading.Thread(target=hold_bench)
+        owner.start()
+        self.assertTrue(entered.wait(timeout=2))
+
+        self.assertTrue(coordinator.public_info()["busy"])
+        with self.assertRaises(HardwareBusyError) as caught:
+            with coordinator.reserve():
+                self.fail("a concurrent request must not enter the physical bench")
+        self.assertEqual(caught.exception.retry_after_seconds, 7)
+
+        release.set()
+        owner.join(timeout=3)
+        self.assertFalse(owner.is_alive())
+        self.assertFalse(coordinator.public_info()["busy"])
+        with coordinator.reserve():
+            self.assertTrue(coordinator.public_info()["busy"])
+
+
+if __name__ == "__main__":
+    unittest.main()