def test_handlerlist_remove():
"""Tests removing an item."""
handler_list = HandlerList()
handler_list.add(mock_callback, 1)
handler_list.add(mock_wrong_callback, 2)
handler_list.remove(mock_callback)
assert len(handler_list) == 1
handler_list.remove(mock_wrong_callback)
assert len(handler_list) == 0
