Fix timezone issues and create coffee view unit test

infoscreen/hsl_fetcher.py

@@ -3,7 +3,8 @@
 import urllib.request
 import json
 import logging
-from datetime import datetime, timedelta
+from datetime import timedelta, datetime
+from django.utils import timezone
 
 from django.conf import settings
 
@@ -20,7 +21,7 @@ class HSLFetcher:
 
     def fetch_if_needed(self):
         """Check if new fetch from HSL API is needed."""
-        if (datetime.now() - HSLFetcher.last_fetched >
+        if (timezone.now() - HSLFetcher.last_fetched >
                 timedelta(minutes=HSLFetcher.INTERVAL)):
             self.fetch()
 
@@ -38,7 +39,7 @@ class HSLFetcher:
 
         arr = []
 
-        time = (datetime.now() +
+        time = (timezone.now() +
                 timedelta(minutes=settings.HSL_DEPARTURE_THRESHOLD))
         time = "{0:02d}{0:02d}".format(time.hour, time.minute)
         for element in data:
@@ -65,7 +66,7 @@ class HSLFetcher:
             obj = model_arr[count - 1]
             obj.data = json_dump
             obj.save()
-        now = datetime.now()
+        now = timezone.now()
         HSLFetcher.last_fetched = now
 
         logging.info(