Ensure threaded servers are killed after test failures

panel/io/server.py

@@ -538,6 +538,8 @@ def serve(panels, port=0, address=None, websocket_origin=None, loop=None,
         server = StoppableThread(
             target=get_server, io_loop=loop, args=(panels,), kwargs=kwargs
         )
+        server_id = kwargs.get('server_id', uuid.uuid4().hex)
+        state._threads[server_id] = server
         server.start()
     else:
         server = get_server(panels, **kwargs)

panel/io/state.py

@@ -84,6 +84,7 @@ class _state(param.Parameterized):
 
     # An index of all currently active servers
     _servers = {}
+    _threads = {}
 
     # Jupyter display handles
     _handles = {}
@@ -260,6 +261,12 @@ def kill_all_servers(self):
         """
         Stop all servers and clear them from the current state.
         """
+        for thread in self._threads.values():
+            try:
+                thread.stop()
+            except Exception:
+                pass
+        self._threads = {}
         for server_id in self._servers:
             try:
                 self._servers[server_id][0].stop()

panel/tests/conftest.py

@@ -163,3 +163,12 @@ def set_env_var(env_var, value):
         del os.environ[env_var]
     else:
         os.environ[env_var] = old_value
+
+
+@pytest.fixture(autouse=True)
+def server_cleanup():
+    """
+    Clean up after test fails
+    """
+    yield
+    state.kill_all_servers()