diff --git a/SAS/TMSS/backend/services/precalculations_service/test/t_precalculations_service.py b/SAS/TMSS/backend/services/precalculations_service/test/t_precalculations_service.py
index 375695eb1ac9697c9bb57f3ead7d82a921160b39..1e077ff0149eb97dc13ddb0c5f5c150eeb8caec9 100644
--- a/SAS/TMSS/backend/services/precalculations_service/test/t_precalculations_service.py
+++ b/SAS/TMSS/backend/services/precalculations_service/test/t_precalculations_service.py
@@ -193,6 +193,34 @@ class TestPreCalculationService(unittest.TestCase):
         st_objects = StationTimeline.objects.filter(timestamp=datetime.date.today())
         self.assertEqual(len(st_objects), nbr_stations)
 
+    def test_all_stations_calculated_with_two_jobs_started(self):
+        """
+        Test if starting two jobs of (pre)calculation service results in no Exception, there are no
+        duplicate data stored (covered by the Constraints in the model)
+        It will test the scheduler with interval of 20 seconds, to make sure one interval after the start has been passed
+        """
+        # Import here otherwise you get
+        # "django.core.exceptions.ImproperlyConfigured: Requested setting INSTALLED_APPS, but settings are not configured. You must either define the environment variable DJANGO_SETTINGS_MODULE or call settings.configure() before accessing settings."
+        from lofar.sas.tmss.tmss.tmssapp.conversions import get_all_stations
+        from lofar.sas.tmss.tmss.tmssapp.models.calculations import StationTimeline
+
+        nbr_stations = len(get_all_stations())
+        # Initially there should be no data
+        self.assertEqual(len(StationTimeline.objects.all()), 0)
+        # Now we are going to create and start the calculation service with an interval of 20 sec
+        # nbr days to calculate ahead is 1 and nbr days before today 0 ->  so it start with 'today' and after ~20 seconds
+        # 'tomorrow' etc..
+        job = create_service_job_for_sunrise_and_sunset_calculations(20, 1, 0)
+        job2 = create_service_job_for_sunrise_and_sunset_calculations(20, 1, 0)
+
+        job.start()
+        job2.start()
+        time.sleep(22)
+        job.stop()
+        job2.stop()
+        # Check what have been created should only be today and tomorrow
+        st_objects = StationTimeline.objects.all()
+        self.assertGreaterEqual(len(st_objects), 2 * nbr_stations)
 
 
 if __name__ == '__main__':