more cleanup

jupyter_client/client.py

@@ -116,6 +116,10 @@ def _context_default(self) -> zmq.asyncio.Context:
     # flag for whether execute requests should be allowed to call raw_input:
     allow_stdin: bool = True
 
+    def __del__(self):
+        """Destroy our context when we are garbage collected."""
+        self.context.destroy()
+
     # --------------------------------------------------------------------------
     # Channel proxy methods
     # --------------------------------------------------------------------------
@@ -320,7 +324,6 @@ def stop_channels(self) -> None:
             self.control_channel.stop()
         if self._created_context:
             self._created_context = False
-            self.context.destroy()
 
     @property
     def channels_running(self) -> bool:

jupyter_client/tests/test_multikernelmanager.py

@@ -160,8 +160,10 @@ def test_start_sequence_ipc_kernels(self):
 
     def tcp_lifecycle_with_loop(self):
         # Ensure each thread has an event loop
-        asyncio.set_event_loop(asyncio.new_event_loop())
+        loop = asyncio.new_event_loop()
+        asyncio.set_event_loop(loop)
         self.test_tcp_lifecycle()
+        loop.close()
 
     def test_start_parallel_thread_kernels(self):
         self.test_tcp_lifecycle()