Refactor FSMAware part from FSMAwareEH to a separate class

lib/tfw/event_handler_base.py

@@ -106,25 +106,17 @@ class EventHandlerBase(ABC):
         pass
 
 
-class FSMAwareEventHandler(EventHandlerBase, ABC):
-    # pylint: disable=abstract-method
-    """
-    Abstract base class for EventHandlers which automatically
-    keep track of the state of the TFW FSM.
-    """
-    def __init__(self, key):
-        super().__init__(key)
-        self.subscribe('fsm_update')
+class FSMAware:
+    def __init__(self):
         self.fsm_state = None
         self.in_accepted_state = False
         self._auth_key = KeyManager().auth_key
 
-    def dispatch_handling(self, message):
-        if message['key'] == 'fsm_update':
-            if verify_message(self._auth_key, message):
+    def update_fsm_data(self, message):
+        if message['key'] == 'fsm_update' and verify_message(self._auth_key, message):
             self._handle_fsm_update(message)
-            return None
-        return super().dispatch_handling(message)
+            return True
+        return False
 
     def _handle_fsm_update(self, message):
         try:
@@ -144,6 +136,23 @@ class FSMAwareEventHandler(EventHandlerBase, ABC):
         pass
 
 
+class FSMAwareEventHandler(EventHandlerBase, FSMAware, ABC):
+    # pylint: disable=abstract-method
+    """
+    Abstract base class for EventHandlers which automatically
+    keep track of the state of the TFW FSM.
+    """
+    def __init__(self, key):
+        EventHandlerBase.__init__(self, key)
+        FSMAware.__init__(self)
+        self.subscribe('fsm_update')
+
+    def dispatch_handling(self, message):
+        if self.update_fsm_data(message):
+            return None
+        return super().dispatch_handling(message)
+
+
 class BroadcastingEventHandler(EventHandlerBase, ABC):
     # pylint: disable=abstract-method
     """