feat(nimbus): Should skip same day alert for unenrollments (#15284)

Because

- If the enrollment just started and the job task ran just after that,
then it may notifies the users false positive about enrollment
monitoring, we should wait at least a day and then should notify on the
next job task run

This commit

- Skips the alert and only sends the alert if its more than 1 day

Fixes #15221

---------

Co-authored-by: Yashika Khurana <[email protected]>

Author: yashikakhurana

experimenter/experimenter/experiments/constants.py

@@ -1173,6 +1173,8 @@ class FirefoxLabsGroups(models.TextChoices):
 
     EXPOSURE_CLIENT_CUTOFF = 10
 
+    MONITORING_ALERT_MINIMUM_DAYS = 1
+
 
 EXTERNAL_URLS = {
     "SIGNOFF_QA": "https://experimenter.info/workflow/risk-mitigation#qa-sign-off",

experimenter/experimenter/slack/tasks.py

@@ -1,3 +1,4 @@
+import datetime
 import logging
 from datetime import timedelta
 
@@ -426,6 +427,11 @@ def _check_monitoring_alerts(experiment):
     if not experiment.monitoring_data:
         return
 
+    if experiment.start_date and (
+        datetime.date.today() - experiment.start_date
+    ) < datetime.timedelta(days=NimbusConstants.MONITORING_ALERT_MINIMUM_DAYS):
+        return
+
     try:
         is_spike, rate = check_unenrollment_spike(experiment.monitoring_data)
         if is_spike:

experimenter/experimenter/slack/tests/test_tasks.py

@@ -1,3 +1,4 @@
+import datetime
 from datetime import timedelta
 from unittest import mock
 
@@ -1039,6 +1040,21 @@ def test_skips_when_monitoring_data_is_none(self):
 
         self.assertEqual(NimbusAlert.objects.filter(experiment=experiment).count(), 0)
 
+    def test_skips_when_experiment_started_less_than_minimum_days_ago(self):
+        experiment = NimbusExperimentFactory.create_with_lifecycle(
+            NimbusExperimentFactory.Lifecycles.LIVE_ENROLLING,
+            monitoring_data=_SPIKE_MONITORING_DATA,
+            start_date=datetime.date.today()
+            - datetime.timedelta(days=NimbusConstants.MONITORING_ALERT_MINIMUM_DAYS - 1),
+        )
+        with mock.patch(
+            "experimenter.slack.tasks.send_slack_notification"
+        ) as mock_send_slack:
+            tasks._check_monitoring_alerts(experiment)
+            mock_send_slack.assert_not_called()
+
+        self.assertEqual(NimbusAlert.objects.filter(experiment=experiment).count(), 0)
+
     def test_sends_unenrollment_spike_alert(self):
         experiment = NimbusExperimentFactory.create_with_lifecycle(
             NimbusExperimentFactory.Lifecycles.LIVE_ENROLLING,