outsource _switcher to make it easily testable;

test vehicle props;
test traffic light _switcher;

components/i_feed/devices/traffic_light.py

@@ -56,23 +56,10 @@ class TrafficLight:
 
     def start(self):
         """
-        Starts the traffic light by spawning a new thread. It toggles its state every self.switching_time / SCALING
-        seconds. When it switches, it notifies the orchestrator with self.send_status_update().
+        Starts the traffic light by spawning a new thread..
         """
         self.running = True
-
-        def switcher():
-            num_colors = len(TrafficLightColor)
-            # set current color to the one before starting color, because switch immediately happens in loop
-            # therefore it sleeps on the end of the loop and first status is immediately sent to msg broker
-            self.current_color = TrafficLightColor((self._starting_color.value - 1) % num_colors)
-            while self.running:
-                self.current_color = TrafficLightColor((self.current_color.value + 1) % num_colors)
-                self.last_switch = datetime.now()
-                self.send_status_update()
-                time.sleep(self.switching_time / SCALING)
-
-        self._t = threading.Thread(target=switcher)
+        self._t = threading.Thread(target=self._switcher)
         self._t.start()
 
     def stop(self):
@@ -91,6 +78,21 @@ class TrafficLight:
         self._tl_mb.send(pickle.dumps(
             TrafficLightState(tlid=self.tlid, color=self.current_color, last_switch=self.last_switch)))
 
+    def _switcher(self):
+        """
+        Toggles the traffic lights state every self.switching_time / SCALING seconds.
+        When it switches, it notifies the orchestrator with self.send_status_update()
+        """
+        num_colors = len(TrafficLightColor)
+        # set current color to the one before starting color, because switch immediately happens in loop
+        # therefore it sleeps on the end of the loop and first status is immediately sent to msg broker
+        self.current_color = TrafficLightColor((self._starting_color.value - 1) % num_colors)
+        while self.running:
+            self.current_color = TrafficLightColor((self.current_color.value + 1) % num_colors)
+            self.last_switch = datetime.now()
+            self.send_status_update()
+            time.sleep(self.switching_time / SCALING)
+
 
 if __name__ == '__main__':
     ...