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__':
     ...

components/i_feed/test_ifeed.py

@@ -0,0 +1,103 @@
+import datetime
+import pickle
+import time
+import unittest
+from unittest.mock import patch
+
+import geopy
+from dse_shared_libs.daf import DAF
+from dse_shared_libs.target_velocity import TargetVelocity
+from dse_shared_libs.traffic_light_color import TrafficLightColor
+
+from components.i_feed.devices.traffic_light import TrafficLight
+from devices.vehicle import Vehicle
+from dse_shared_libs.mock.rabbit_mq_mocks import MyBlockingConnection
+
+
+class TestVehicle(unittest.TestCase):
+    def setUp(self) -> None:
+        with patch('pika.BlockingConnection', MyBlockingConnection):
+            self.vin = 'my_vin'
+            self.starting_velocity = 130
+            self.starting_point = geopy.Point(0, 0, 0)
+            self.timestamp = datetime.datetime.now()
+
+            self.v = Vehicle(
+                vin=self.vin,
+                starting_point=self.starting_point,
+                starting_velocity=self.starting_velocity
+            )
+
+            self.v.last_update = self.timestamp
+            self.v._driven_kms = 0
+
+    def test_nce_prop(self):
+        with patch('time.sleep', return_value=None):
+            # initially false
+            self.assertEqual(self.v.nce, False)
+            # get past nce km
+            self.v._driven_kms = 3
+            # now nce should fire
+            self.assertEqual(self.v.nce, True)
+            # second call is false again
+            self.assertEqual(self.v.nce, False)
+
+    def test_daf_prop(self):
+        # test if daf object created properly
+        daf = DAF(vehicle_identification_number=self.vin,
+                  gps_location=self.starting_point,
+                  velocity=self.starting_velocity,
+                  timestamp=self.timestamp,
+                  near_crash_event=False)
+        self.assertEqual(self.v.daf, daf)
+
+    def test_current_location_prop(self):
+        # initial position should be starting point
+        self.assertEqual(self.v.gps_location, self.starting_point)
+
+        # lets say last time was about an hour ago
+        self.v.last_update = self.timestamp - datetime.timedelta(hours=1)
+
+        # we drive "almost" directly north
+        loc = self.v.gps_location
+        self.assertEqual(round(loc.latitude, 2), 1.17)
+        self.assertEqual(round(loc.longitude, 2), 0.04)
+
+    def test_driven_kms_prop(self):
+        # initial driven kms are 0
+        self.assertEqual(self.v.driven_kms, '0km')
+
+        # alter driven kms
+        self.v._driven_kms = 44.24552
+        # will be rounded to 2 digits
+        self.assertEqual(self.v.driven_kms, '44.25km')
+
+    def test_new_velocity(self):
+        # starting velocity is set to 130
+        self.assertEqual(self.v.velocity, 130)
+
+        # we get a new velocity, lets say 55 ...
+        tv = TargetVelocity(vin='my_vin', target_velocity=55, timestamp=self.timestamp)
+        self.v.new_velocity(pickle.dumps(tv))
+        # then the vehicle should comply with that
+        self.assertEqual(self.v.velocity, 55)
+
+
+class TestTrafficLight(unittest.TestCase):
+    def setUp(self) -> None:
+        with patch('pika.BlockingConnection', MyBlockingConnection):
+            self.tl = TrafficLight(tlid='my_tl',
+                                   switching_time=1,
+                                   starting_color=TrafficLightColor.RED)
+
+    def tearDown(self) -> None:
+        self.tl.stop()
+
+    def test_switching(self):
+        self.assertFalse(hasattr(self.tl, 'current_color'))
+        self.tl.start()
+        self.assertEqual(self.tl.current_color, TrafficLightColor.RED)
+        time.sleep(1.2)
+        self.assertEqual(self.tl.current_color, TrafficLightColor.GREEN)
+        time.sleep(1)
+        self.assertEqual(self.tl.current_color, TrafficLightColor.RED)