From 08c1ad75c8c520e39d4e8ede6622064ea97f7143 Mon Sep 17 00:00:00 2001
From: Kenneth Kehl <@kkehl@flexion.us>
Date: Wed, 10 May 2023 08:39:50 -0700
Subject: [PATCH 1/6] notify-260 remove server-side timezone handling

---
 app/celery/nightly_tasks.py                   | 17 ++++-----
 app/celery/reporting_tasks.py                 |  5 +--
 .../performance_platform_client.py            |  3 +-
 app/commands.py                               |  6 +--
 app/dao/complaint_dao.py                      |  6 +--
 app/dao/date_util.py                          | 26 +++----------
 app/dao/fact_billing_dao.py                   | 13 +++----
 app/dao/fact_notification_status_dao.py       | 18 ++++-----
 app/dao/notifications_dao.py                  |  6 +--
 app/dao/provider_details_dao.py               |  5 +--
 app/dao/services_dao.py                       |  9 ++---
 app/models.py                                 |  4 +-
 app/performance_platform/processing_time.py   |  6 +--
 app/platform_stats/rest.py                    |  6 +--
 app/service/rest.py                           |  5 +--
 app/service/statistics.py                     |  4 +-
 app/utils.py                                  | 11 +++---
 tests/app/celery/test_nightly_tasks.py        | 22 +++++------
 tests/app/celery/test_reporting_tasks.py      |  6 +--
 .../notification_dao/test_notification_dao.py |  2 +-
 tests/app/dao/test_complaint_dao.py           |  2 +-
 tests/app/dao/test_date_utils.py              | 23 ++++++-----
 tests/app/dao/test_fact_billing_dao.py        | 29 +++++++-------
 tests/app/dao/test_inbound_sms_dao.py         | 22 +++++------
 tests/app/dao/test_jobs_dao.py                |  4 +-
 tests/app/dao/test_services_dao.py            |  4 +-
 tests/app/inbound_sms/test_rest.py            |  4 +-
 tests/app/job/test_rest.py                    |  4 +-
 tests/app/service/test_utils.py               |  2 +-
 tests/app/test_model.py                       |  6 +--
 tests/app/test_utils.py                       | 38 +++++++++----------
 31 files changed, 143 insertions(+), 175 deletions(-)

diff --git a/app/celery/nightly_tasks.py b/app/celery/nightly_tasks.py
index ce98dd27c..07a9fd31b 100644
--- a/app/celery/nightly_tasks.py
+++ b/app/celery/nightly_tasks.py
@@ -1,7 +1,6 @@
 from datetime import datetime, timedelta
 
 from flask import current_app
-from notifications_utils.timezones import convert_utc_to_local_timezone
 from sqlalchemy.exc import SQLAlchemyError
 
 from app import notify_celery
@@ -25,7 +24,7 @@
     fetch_service_data_retention_for_all_services_by_notification_type,
 )
 from app.models import EMAIL_TYPE, SMS_TYPE, FactProcessingTime
-from app.utils import get_local_midnight_in_utc
+from app.utils import get_midnight_in_utc
 
 
 @notify_celery.task(name="remove_sms_email_jobs")
@@ -64,9 +63,8 @@ def _delete_notifications_older_than_retention_by_type(notification_type):
     flexible_data_retention = fetch_service_data_retention_for_all_services_by_notification_type(notification_type)
 
     for f in flexible_data_retention:
-        day_to_delete_backwards_from = get_local_midnight_in_utc(
-            convert_utc_to_local_timezone(datetime.utcnow()).date() - timedelta(days=f.days_of_retention)
-        )
+        day_to_delete_backwards_from = get_midnight_in_utc(datetime.utcnow()).date() \
+                                       - timedelta(days=f.days_of_retention)
 
         delete_notifications_for_service_and_type.apply_async(queue=QueueNames.REPORTING, kwargs={
             'service_id': f.service_id,
@@ -74,9 +72,8 @@ def _delete_notifications_older_than_retention_by_type(notification_type):
             'datetime_to_delete_before': day_to_delete_backwards_from
         })
 
-    seven_days_ago = get_local_midnight_in_utc(
-        convert_utc_to_local_timezone(datetime.utcnow()).date() - timedelta(days=7)
-    )
+    seven_days_ago = get_midnight_in_utc(datetime.utcnow()).date() - timedelta(days=7)
+
     service_ids_with_data_retention = {x.service_id for x in flexible_data_retention}
 
     # get a list of all service ids that we'll need to delete for. Typically that might only be 5% of services.
@@ -168,8 +165,8 @@ def save_daily_notification_processing_time(local_date=None):
     else:
         local_date = datetime.strptime(local_date, "%Y-%m-%d").date()
 
-    start_time = get_local_midnight_in_utc(local_date)
-    end_time = get_local_midnight_in_utc(local_date + timedelta(days=1))
+    start_time = get_midnight_in_utc(local_date)
+    end_time = get_midnight_in_utc(local_date + timedelta(days=1))
     result = dao_get_notifications_processing_time_stats(start_time, end_time)
     insert_update_processing_time(
         FactProcessingTime(
diff --git a/app/celery/reporting_tasks.py b/app/celery/reporting_tasks.py
index 123eb8ced..5229f7ec6 100644
--- a/app/celery/reporting_tasks.py
+++ b/app/celery/reporting_tasks.py
@@ -1,7 +1,6 @@
 from datetime import datetime, timedelta
 
 from flask import current_app
-from notifications_utils.timezones import convert_utc_to_local_timezone
 
 from app import notify_celery
 from app.config import QueueNames
@@ -21,7 +20,7 @@ def create_nightly_billing(day_start=None):
     # day_start is a datetime.date() object. e.g.
     # up to 4 days of data counting back from day_start is consolidated
     if day_start is None:
-        day_start = convert_utc_to_local_timezone(datetime.utcnow()).date() - timedelta(days=1)
+        day_start = datetime.utcnow().date() - timedelta(days=1)
     else:
         # When calling the task its a string in the format of "YYYY-MM-DD"
         day_start = datetime.strptime(day_start, "%Y-%m-%d").date()
@@ -83,7 +82,7 @@ def create_nightly_notification_status():
         mean the aggregated results are temporarily incorrect.
     """
 
-    yesterday = convert_utc_to_local_timezone(datetime.utcnow()).date() - timedelta(days=1)
+    yesterday = datetime.utcnow().date() - timedelta(days=1)
 
     for notification_type in [SMS_TYPE, EMAIL_TYPE]:
         days = 4
diff --git a/app/clients/performance_platform/performance_platform_client.py b/app/clients/performance_platform/performance_platform_client.py
index 6a27b402f..6448fca75 100644
--- a/app/clients/performance_platform/performance_platform_client.py
+++ b/app/clients/performance_platform/performance_platform_client.py
@@ -3,7 +3,6 @@
 
 import requests
 from flask import current_app
-from notifications_utils.timezones import convert_utc_to_local_timezone
 
 
 class PerformancePlatformClient:
@@ -55,7 +54,7 @@ def format_payload(*, dataset, start_time, group_name, group_value, count, perio
         :param period - the period that this data covers - "day", "week", "month", "quarter".
         """
         payload = {
-            '_timestamp': convert_utc_to_local_timezone(start_time).isoformat(),
+            '_timestamp': start_time,
             'service': 'govuk-notify',
             'dataType': dataset,
             'period': period,
diff --git a/app/commands.py b/app/commands.py
index 7a8c99d7b..e0f676b08 100644
--- a/app/commands.py
+++ b/app/commands.py
@@ -62,7 +62,7 @@
     TemplateHistory,
     User,
 )
-from app.utils import get_local_midnight_in_utc
+from app.utils import get_midnight_in_utc
 
 
 @click.group(name='command', help='Additional commands')
@@ -192,8 +192,8 @@ def rebuild_ft_data(process_day, service):
         rebuild_ft_data(day, service_id)
     else:
         services = get_service_ids_that_need_billing_populated(
-            get_local_midnight_in_utc(day),
-            get_local_midnight_in_utc(day + timedelta(days=1))
+            get_midnight_in_utc(day),
+            get_midnight_in_utc(day + timedelta(days=1))
         )
         for row in services:
             rebuild_ft_data(day, row.service_id)
diff --git a/app/dao/complaint_dao.py b/app/dao/complaint_dao.py
index 819a3666f..9a9351912 100644
--- a/app/dao/complaint_dao.py
+++ b/app/dao/complaint_dao.py
@@ -6,7 +6,7 @@
 from app import db
 from app.dao.dao_utils import autocommit
 from app.models import Complaint
-from app.utils import get_local_midnight_in_utc
+from app.utils import get_midnight_in_utc
 
 
 @autocommit
@@ -28,7 +28,7 @@ def fetch_complaints_by_service(service_id):
 
 
 def fetch_count_of_complaints(start_date, end_date):
-    start_date = get_local_midnight_in_utc(start_date)
-    end_date = get_local_midnight_in_utc(end_date + timedelta(days=1))
+    start_date = get_midnight_in_utc(start_date)
+    end_date = get_midnight_in_utc(end_date + timedelta(days=1))
 
     return Complaint.query.filter(Complaint.created_at >= start_date, Complaint.created_at < end_date).count()
diff --git a/app/dao/date_util.py b/app/dao/date_util.py
index 94d6cb3cb..980661cf7 100644
--- a/app/dao/date_util.py
+++ b/app/dao/date_util.py
@@ -1,20 +1,13 @@
 from datetime import date, datetime, time, timedelta
 
-import pytz
-from notifications_utils.timezones import (
-    convert_local_timezone_to_utc,
-    convert_utc_to_local_timezone,
-    local_timezone,
-)
-
 
 def get_months_for_financial_year(year):
     return [
-        convert_local_timezone_to_utc(month) for month in (
+        month for month in (
             get_months_for_year(4, 13, year)
             + get_months_for_year(1, 4, year + 1)
         )
-        if convert_local_timezone_to_utc(month) < datetime.now()
+        if month < datetime.now()
     ]
 
 
@@ -30,8 +23,8 @@ def get_financial_year_dates(year):
     year_start_datetime, year_end_datetime = get_financial_year(year)
 
     return (
-        convert_utc_to_local_timezone(year_start_datetime).date(),
-        convert_utc_to_local_timezone(year_end_datetime).date()
+        year_start_datetime.date(),
+        year_end_datetime.date()
     )
 
 
@@ -44,14 +37,7 @@ def get_current_financial_year():
 
 
 def get_april_fools(year):
-    """
-     This function converts the start of the financial year April 1, 00:00 as BST (British Standard Time) to UTC,
-     the tzinfo is lastly removed from the datetime because the database stores the timestamps without timezone.
-     :param year: the year to calculate the April 1, 00:00 BST for
-     :return: the datetime of April 1 for the given year, for example 2016 = 2016-03-31 23:00:00
-    """
-    return local_timezone.localize(
-        datetime(year, 4, 1, 0, 0, 0)).astimezone(pytz.UTC).replace(tzinfo=None)
+    return datetime(year, 4, 1, 0, 0, 0)
 
 
 def get_month_start_and_end_date_in_utc(month_year):
@@ -64,7 +50,7 @@ def get_month_start_and_end_date_in_utc(month_year):
     _, num_days = calendar.monthrange(month_year.year, month_year.month)
     first_day = datetime(month_year.year, month_year.month, 1, 0, 0, 0)
     last_day = datetime(month_year.year, month_year.month, num_days, 23, 59, 59, 99999)
-    return convert_local_timezone_to_utc(first_day), convert_local_timezone_to_utc(last_day)
+    return first_day, last_day
 
 
 def get_current_financial_year_start_year():
diff --git a/app/dao/fact_billing_dao.py b/app/dao/fact_billing_dao.py
index 187b2c860..7cb5d97e5 100644
--- a/app/dao/fact_billing_dao.py
+++ b/app/dao/fact_billing_dao.py
@@ -1,7 +1,6 @@
 from datetime import date, datetime, timedelta
 
 from flask import current_app
-from notifications_utils.timezones import convert_utc_to_local_timezone
 from sqlalchemy import Date, Integer, and_, desc, func, union
 from sqlalchemy.dialects.postgresql import insert
 from sqlalchemy.sql.expression import case, literal
@@ -27,7 +26,7 @@
     Rate,
     Service,
 )
-from app.utils import get_local_midnight_in_utc
+from app.utils import get_midnight_in_utc
 
 
 def fetch_sms_free_allowance_remainder_until_date(end_date):
@@ -179,7 +178,7 @@ def fetch_monthly_billing_for_year(service_id, year):
     we also update the table on-the-fly if we need accurate data for this year.
     """
     _, year_end = get_financial_year_dates(year)
-    today = convert_utc_to_local_timezone(datetime.utcnow()).date()
+    today = datetime.utcnow().date()
 
     # if year end date is less than today, we are calculating for data in the past and have no need for deltas.
     if year_end >= today:
@@ -330,8 +329,8 @@ def delete_billing_data_for_service_for_day(process_day, service_id):
 
 
 def fetch_billing_data_for_day(process_day, service_id=None, check_permissions=False):
-    start_date = get_local_midnight_in_utc(process_day)
-    end_date = get_local_midnight_in_utc(process_day + timedelta(days=1))
+    start_date = get_midnight_in_utc(process_day)
+    end_date = get_midnight_in_utc(process_day + timedelta(days=1))
     current_app.logger.info("Populate ft_billing for {} to {}".format(start_date, end_date))
     transit_data = []
     if not service_id:
@@ -430,7 +429,7 @@ def get_service_ids_that_need_billing_populated(start_date, end_date):
 def get_rate(
     rates, notification_type, date
 ):
-    start_of_day = get_local_midnight_in_utc(date)
+    start_of_day = get_midnight_in_utc(date)
 
     if notification_type == SMS_TYPE:
         return next(
@@ -624,7 +623,7 @@ def query_organisation_sms_usage_for_year(organisation_id, year):
 
 def fetch_usage_year_for_organisation(organisation_id, year):
     year_start, year_end = get_financial_year_dates(year)
-    today = convert_utc_to_local_timezone(datetime.utcnow()).date()
+    today = datetime.utcnow().date()
     services = dao_get_organisation_live_services(organisation_id)
 
     # if year end date is less than today, we are calculating for data in the past and have no need for deltas.
diff --git a/app/dao/fact_notification_status_dao.py b/app/dao/fact_notification_status_dao.py
index e4ab55203..aa884cc2d 100644
--- a/app/dao/fact_notification_status_dao.py
+++ b/app/dao/fact_notification_status_dao.py
@@ -28,16 +28,16 @@
     Template,
 )
 from app.utils import (
-    get_local_midnight_in_utc,
     get_local_month_from_utc_column,
+    get_midnight_in_utc,
     midnight_n_days_ago,
 )
 
 
 @autocommit
 def update_fact_notification_status(process_day, notification_type, service_id):
-    start_date = get_local_midnight_in_utc(process_day)
-    end_date = get_local_midnight_in_utc(process_day + timedelta(days=1))
+    start_date = get_midnight_in_utc(process_day)
+    end_date = get_midnight_in_utc(process_day + timedelta(days=1))
 
     # delete any existing rows in case some no longer exist e.g. if all messages are sent
     FactNotificationStatus.query.filter(
@@ -112,8 +112,8 @@ def fetch_notification_status_for_service_for_day(bst_day, service_id):
         Notification.status.label('notification_status'),
         func.count().label('count')
     ).filter(
-        Notification.created_at >= get_local_midnight_in_utc(bst_day),
-        Notification.created_at < get_local_midnight_in_utc(bst_day + timedelta(days=1)),
+        Notification.created_at >= get_midnight_in_utc(bst_day),
+        Notification.created_at < get_midnight_in_utc(bst_day + timedelta(days=1)),
         Notification.service_id == service_id,
         Notification.key_type != KEY_TYPE_TEST
     ).group_by(
@@ -142,7 +142,7 @@ def fetch_notification_status_for_service_for_today_and_7_previous_days(service_
         *([Notification.template_id] if by_template else []),
         func.count().label('count')
     ).filter(
-        Notification.created_at >= get_local_midnight_in_utc(now),
+        Notification.created_at >= get_midnight_in_utc(now),
         Notification.service_id == service_id,
         Notification.key_type != KEY_TYPE_TEST
     ).group_by(
@@ -188,7 +188,7 @@ def fetch_notification_status_totals_for_all_services(start_date, end_date):
         FactNotificationStatus.notification_status,
         FactNotificationStatus.key_type,
     )
-    today = get_local_midnight_in_utc(datetime.utcnow())
+    today = get_midnight_in_utc(datetime.utcnow())
     if start_date <= datetime.utcnow().date() <= end_date:
         stats_for_today = db.session.query(
             Notification.notification_type.cast(db.Text).label('notification_type'),
@@ -265,7 +265,7 @@ def fetch_stats_for_all_services_by_date_range(start_date, end_date, include_fro
         stats = stats.filter(FactNotificationStatus.key_type != KEY_TYPE_TEST)
 
     if start_date <= datetime.utcnow().date() <= end_date:
-        today = get_local_midnight_in_utc(datetime.utcnow())
+        today = get_midnight_in_utc(datetime.utcnow())
         subquery = db.session.query(
             Notification.notification_type.cast(db.Text).label('notification_type'),
             Notification.status.label('status'),
@@ -357,7 +357,7 @@ def fetch_monthly_template_usage_for_service(start_date, end_date, service_id):
     )
 
     if start_date <= datetime.utcnow() <= end_date:
-        today = get_local_midnight_in_utc(datetime.utcnow())
+        today = get_midnight_in_utc(datetime.utcnow())
         month = get_local_month_from_utc_column(Notification.created_at)
 
         stats_for_today = db.session.query(
diff --git a/app/dao/notifications_dao.py b/app/dao/notifications_dao.py
index d560e61eb..72a96d22b 100644
--- a/app/dao/notifications_dao.py
+++ b/app/dao/notifications_dao.py
@@ -35,7 +35,7 @@
 )
 from app.utils import (
     escape_special_characters,
-    get_local_midnight_in_utc,
+    get_midnight_in_utc,
     midnight_n_days_ago,
 )
 
@@ -579,8 +579,8 @@ def get_service_ids_with_notifications_before(notification_type, timestamp):
 
 
 def get_service_ids_with_notifications_on_date(notification_type, date):
-    start_date = get_local_midnight_in_utc(date)
-    end_date = get_local_midnight_in_utc(date + timedelta(days=1))
+    start_date = get_midnight_in_utc(date)
+    end_date = get_midnight_in_utc(date + timedelta(days=1))
 
     notification_table_query = db.session.query(
         Notification.service_id.label('service_id')
diff --git a/app/dao/provider_details_dao.py b/app/dao/provider_details_dao.py
index 2fc03d424..e32e26e1e 100644
--- a/app/dao/provider_details_dao.py
+++ b/app/dao/provider_details_dao.py
@@ -1,7 +1,6 @@
 from datetime import datetime, timedelta
 
 from flask import current_app
-from notifications_utils.timezones import convert_utc_to_local_timezone
 from sqlalchemy import asc, desc, func
 
 from app import db
@@ -155,8 +154,8 @@ def _update_provider_details_without_commit(provider_details):
 def dao_get_provider_stats():
     # this query does not include the current day since the task to populate ft_billing runs overnight
 
-    current_local_datetime = convert_utc_to_local_timezone(datetime.utcnow())
-    first_day_of_the_month = current_local_datetime.date().replace(day=1)
+    current_datetime = datetime.utcnow()
+    first_day_of_the_month = current_datetime.date().replace(day=1)
 
     subquery = db.session.query(
         FactBilling.provider,
diff --git a/app/dao/services_dao.py b/app/dao/services_dao.py
index 33caf9195..4456d32b2 100644
--- a/app/dao/services_dao.py
+++ b/app/dao/services_dao.py
@@ -42,7 +42,7 @@
 from app.utils import (
     escape_special_characters,
     get_archived_db_column_value,
-    get_local_midnight_in_utc,
+    get_midnight_in_utc,
 )
 
 DEFAULT_SERVICE_PERMISSIONS = [
@@ -388,8 +388,7 @@ def _delete_commit(query):
 
 def dao_fetch_todays_stats_for_service(service_id):
     today = date.today()
-    start_date = get_local_midnight_in_utc(today)
-
+    start_date = get_midnight_in_utc(today)
     return db.session.query(
         Notification.notification_type,
         Notification.status,
@@ -406,8 +405,8 @@ def dao_fetch_todays_stats_for_service(service_id):
 
 def dao_fetch_todays_stats_for_all_services(include_from_test_key=True, only_active=True):
     today = date.today()
-    start_date = get_local_midnight_in_utc(today)
-    end_date = get_local_midnight_in_utc(today + timedelta(days=1))
+    start_date = get_midnight_in_utc(today)
+    end_date = get_midnight_in_utc(today + timedelta(days=1))
 
     subquery = db.session.query(
         Notification.notification_type,
diff --git a/app/models.py b/app/models.py
index 31741b41a..50d2bd86b 100644
--- a/app/models.py
+++ b/app/models.py
@@ -17,7 +17,6 @@
     PlainTextEmailTemplate,
     SMSMessageTemplate,
 )
-from notifications_utils.timezones import convert_utc_to_local_timezone
 from sqlalchemy import CheckConstraint, Index, UniqueConstraint
 from sqlalchemy.dialects.postgresql import JSON, JSONB, UUID
 from sqlalchemy.ext.associationproxy import association_proxy
@@ -1503,7 +1502,6 @@ def get_created_by_email_address(self):
             return None
 
     def serialize_for_csv(self):
-        created_at_in_est = convert_utc_to_local_timezone(self.created_at)
         serialized = {
             "row_number": '' if self.job_row_number is None else self.job_row_number + 1,
             "recipient": self.to,
@@ -1512,7 +1510,7 @@ def serialize_for_csv(self):
             "template_type": self.template.template_type,
             "job_name": self.job.original_file_name if self.job else '',
             "status": self.formatted_status,
-            "created_at": created_at_in_est.strftime("%Y-%m-%d %H:%M:%S"),
+            "created_at": self.created_at.strftime("%Y-%m-%d %H:%M:%S"),
             "created_by_name": self.get_created_by_name(),
             "created_by_email_address": self.get_created_by_email_address(),
         }
diff --git a/app/performance_platform/processing_time.py b/app/performance_platform/processing_time.py
index f58c94d43..25e16c5b6 100644
--- a/app/performance_platform/processing_time.py
+++ b/app/performance_platform/processing_time.py
@@ -6,12 +6,12 @@
 from app.dao.notifications_dao import (
     dao_get_total_notifications_sent_per_day_for_performance_platform,
 )
-from app.utils import get_local_midnight_in_utc
+from app.utils import get_midnight_in_utc
 
 
 def send_processing_time_to_performance_platform(local_date):
-    start_time = get_local_midnight_in_utc(local_date)
-    end_time = get_local_midnight_in_utc(local_date + timedelta(days=1))
+    start_time = get_midnight_in_utc(local_date)
+    end_time = get_midnight_in_utc(local_date + timedelta(days=1))
 
     send_processing_time_for_start_and_end(start_time, end_time, local_date)
 
diff --git a/app/platform_stats/rest.py b/app/platform_stats/rest.py
index 554fc3988..fa340450b 100644
--- a/app/platform_stats/rest.py
+++ b/app/platform_stats/rest.py
@@ -17,7 +17,7 @@
 from app.platform_stats.platform_stats_schema import platform_stats_request
 from app.schema_validation import validate
 from app.service.statistics import format_admin_stats
-from app.utils import get_local_midnight_in_utc
+from app.utils import get_midnight_in_utc
 
 platform_stats_blueprint = Blueprint('platform_stats', __name__)
 
@@ -54,8 +54,8 @@ def validate_date_range_is_within_a_financial_year(start_date, end_date):
     if end_date < start_date:
         raise InvalidRequest(message="Start date must be before end date", status_code=400)
 
-    start_fy = get_financial_year_for_datetime(get_local_midnight_in_utc(start_date))
-    end_fy = get_financial_year_for_datetime(get_local_midnight_in_utc(end_date))
+    start_fy = get_financial_year_for_datetime(get_midnight_in_utc(start_date))
+    end_fy = get_financial_year_for_datetime(get_midnight_in_utc(end_date))
 
     if start_fy != end_fy:
         raise InvalidRequest(message="Date must be in a single financial year.", status_code=400)
diff --git a/app/service/rest.py b/app/service/rest.py
index d969f4f5a..abeb41e48 100644
--- a/app/service/rest.py
+++ b/app/service/rest.py
@@ -2,7 +2,6 @@
 from datetime import datetime
 
 from flask import Blueprint, current_app, jsonify, request
-from notifications_utils.timezones import convert_utc_to_local_timezone
 from sqlalchemy.exc import IntegrityError
 from sqlalchemy.orm.exc import NoResultFound
 from werkzeug.datastructures import MultiDict
@@ -500,9 +499,7 @@ def get_monthly_notification_stats(service_id):
 
     now = datetime.utcnow()
     if end_date > now:
-        todays_deltas = fetch_notification_status_for_service_for_day(
-            convert_utc_to_local_timezone(now), service_id=service_id
-        )
+        todays_deltas = fetch_notification_status_for_service_for_day(now, service_id=service_id)
         statistics.add_monthly_notification_status_stats(data, todays_deltas)
 
     return jsonify(data=data)
diff --git a/app/service/statistics.py b/app/service/statistics.py
index e36106f0b..4a45189ad 100644
--- a/app/service/statistics.py
+++ b/app/service/statistics.py
@@ -1,8 +1,6 @@
 from collections import defaultdict
 from datetime import datetime
 
-from notifications_utils.timezones import convert_utc_to_local_timezone
-
 from app.dao.date_util import get_months_for_financial_year
 from app.models import NOTIFICATION_STATUS_TYPES, NOTIFICATION_TYPES
 
@@ -98,7 +96,7 @@ def create_empty_monthly_notification_status_stats_dict(year):
     utc_month_starts = get_months_for_financial_year(year)
     # nested dicts - data[month][template type][status] = count
     return {
-        convert_utc_to_local_timezone(start).strftime('%Y-%m'): {
+        start.strftime('%Y-%m'): {
             template_type: defaultdict(int)
             for template_type in NOTIFICATION_TYPES
         }
diff --git a/app/utils.py b/app/utils.py
index dbd9b3056..622582997 100644
--- a/app/utils.py
+++ b/app/utils.py
@@ -3,7 +3,6 @@
 
 from flask import url_for
 from notifications_utils.template import HTMLEmailTemplate, SMSMessageTemplate
-from notifications_utils.timezones import convert_local_timezone_to_utc
 from sqlalchemy import func
 
 DATETIME_FORMAT_NO_TIMEZONE = "%Y-%m-%d %H:%M:%S.%f"
@@ -49,19 +48,19 @@ def get_template_instance(template, values):
     }[template['template_type']](template, values)
 
 
-def get_local_midnight_in_utc(date):
+def get_midnight_in_utc(date):
     """
-     This function converts date from midnight in local time to UTC,
+     This function converts date to midnight in UTC,
      removing the tzinfo from the datetime because the database stores the timestamps without timezone.
      :param date: the day to calculate the local midnight in UTC for
      :return: the datetime of local midnight in UTC, for example 2016-06-17 = 2016-06-16 23:00:00
     """
-    return convert_local_timezone_to_utc(datetime.combine(date, datetime.min.time()))
+    return datetime.combine(date, datetime.min.time())
 
 
 def get_midnight_for_day_before(date):
     day_before = date - timedelta(1)
-    return get_local_midnight_in_utc(day_before)
+    return get_midnight_in_utc(day_before)
 
 
 def get_local_month_from_utc_column(column):
@@ -95,7 +94,7 @@ def midnight_n_days_ago(number_of_days):
     """
     Returns midnight a number of days ago. Takes care of daylight savings etc.
     """
-    return get_local_midnight_in_utc(datetime.utcnow() - timedelta(days=number_of_days))
+    return get_midnight_in_utc(datetime.utcnow() - timedelta(days=number_of_days))
 
 
 def escape_special_characters(string):
diff --git a/tests/app/celery/test_nightly_tasks.py b/tests/app/celery/test_nightly_tasks.py
index 0599799e4..8c4d50b9e 100644
--- a/tests/app/celery/test_nightly_tasks.py
+++ b/tests/app/celery/test_nightly_tasks.py
@@ -239,11 +239,11 @@ def test_delete_notifications_task_calls_task_for_services_with_data_retention_o
         'service_id': sms_service.id,
         'notification_type': 'sms',
         # three days of retention, its morn of 5th, so we want to keep all messages from 4th, 3rd and 2nd.
-        'datetime_to_delete_before': datetime(2021, 6, 2, 4, 0),
+        'datetime_to_delete_before': date(2021, 6, 2),
     })
 
 
-@freeze_time('2021-04-05 03:00')
+@freeze_time('2021-04-04 23:00')
 def test_delete_notifications_task_calls_task_for_services_with_data_retention_by_looking_at_retention(
     notify_db_session,
     mocker
@@ -262,17 +262,17 @@ def test_delete_notifications_task_calls_task_for_services_with_data_retention_b
         call(queue=ANY, kwargs={
             'service_id': service_14_days.id,
             'notification_type': 'sms',
-            'datetime_to_delete_before': datetime(2021, 3, 21, 4, 0)
+            'datetime_to_delete_before': date(2021, 3, 21)
         }),
         call(queue=ANY, kwargs={
             'service_id': service_3_days.id,
             'notification_type': 'sms',
-            'datetime_to_delete_before': datetime(2021, 4, 1, 4, 0)
+            'datetime_to_delete_before': date(2021, 4, 1)
         }),
     ])
 
 
-@freeze_time('2021-04-03 03:00')
+@freeze_time('2021-04-02 23:00')
 def test_delete_notifications_task_calls_task_for_services_that_have_sent_notifications_recently(
     notify_db_session,
     mocker
@@ -288,13 +288,13 @@ def test_delete_notifications_task_calls_task_for_services_that_have_sent_notifi
     nothing_to_delete_email_template = create_template(service_nothing_to_delete, template_type='email')
 
     # will be deleted as service has no custom retention, but past our default 7 days
-    create_notification(service_will_delete_1.templates[0], created_at=datetime.now() - timedelta(days=8))
-    create_notification(service_will_delete_2.templates[0], created_at=datetime.now() - timedelta(days=8))
+    create_notification(service_will_delete_1.templates[0], created_at=datetime.utcnow() - timedelta(days=8))
+    create_notification(service_will_delete_2.templates[0], created_at=datetime.utcnow() - timedelta(days=8))
 
     # will be kept as it's recent, and we won't run delete_notifications_for_service_and_type
-    create_notification(nothing_to_delete_sms_template, created_at=datetime.now() - timedelta(days=2))
+    create_notification(nothing_to_delete_sms_template, created_at=datetime.utcnow() - timedelta(days=2))
     # this is an old notification, but for email not sms, so we won't run delete_notifications_for_service_and_type
-    create_notification(nothing_to_delete_email_template, created_at=datetime.now() - timedelta(days=8))
+    create_notification(nothing_to_delete_email_template, created_at=datetime.utcnow() - timedelta(days=8))
 
     mock_subtask = mocker.patch('app.celery.nightly_tasks.delete_notifications_for_service_and_type')
 
@@ -305,11 +305,11 @@ def test_delete_notifications_task_calls_task_for_services_that_have_sent_notifi
         call(queue=ANY, kwargs={
             'service_id': service_will_delete_1.id,
             'notification_type': 'sms',
-            'datetime_to_delete_before': datetime(2021, 3, 26, 4, 0)
+            'datetime_to_delete_before': date(2021, 3, 26)
         }),
         call(queue=ANY, kwargs={
             'service_id': service_will_delete_2.id,
             'notification_type': 'sms',
-            'datetime_to_delete_before': datetime(2021, 3, 26, 4, 0)
+            'datetime_to_delete_before': date(2021, 3, 26)
         }),
     ])
diff --git a/tests/app/celery/test_reporting_tasks.py b/tests/app/celery/test_reporting_tasks.py
index 987e4bc8f..fb50c9deb 100644
--- a/tests/app/celery/test_reporting_tasks.py
+++ b/tests/app/celery/test_reporting_tasks.py
@@ -73,7 +73,7 @@ def test_create_nightly_notification_status_triggers_tasks(
     mock_celery.assert_called_with(
         kwargs={
             'service_id': sample_service.id,
-            'process_day': '2019-07-30',
+            'process_day': '2019-07-31',
             'notification_type': SMS_TYPE
         },
         queue=QueueNames.REPORTING
@@ -352,7 +352,7 @@ def test_create_nightly_billing_for_day_use_BST(
     )
 
     create_notification(
-        created_at=datetime(2018, 3, 26, 3, 59),
+        created_at=datetime(2018, 3, 25, 23, 59),
         template=sample_template,
         status='delivered',
         rate_multiplier=1.0,
@@ -361,7 +361,7 @@ def test_create_nightly_billing_for_day_use_BST(
 
     # too early
     create_notification(
-        created_at=datetime(2018, 3, 25, 3, 59),
+        created_at=datetime(2018, 3, 24, 23, 59),
         template=sample_template,
         status='delivered',
         rate_multiplier=1.0,
diff --git a/tests/app/dao/notification_dao/test_notification_dao.py b/tests/app/dao/notification_dao/test_notification_dao.py
index 34aac0466..5eecdd087 100644
--- a/tests/app/dao/notification_dao/test_notification_dao.py
+++ b/tests/app/dao/notification_dao/test_notification_dao.py
@@ -1495,7 +1495,7 @@ def test_notifications_not_yet_sent_return_no_rows(sample_service, notification_
 @pytest.mark.parametrize('created_at_utc,date_to_check,expected_count', [
     # Clocks change on the 27th of March 2022, so the query needs to look at the
     # time range 00:00 - 23:00 (UTC) thereafter.
-    ('2022-03-27T00:30', date(2022, 3, 27), 0),  # 27/03 00:30 GMT
+    ('2022-03-27T00:30', date(2022, 3, 27), 1),  # 27/03 00:30 GMT
     ('2022-03-27T22:30', date(2022, 3, 27), 1),  # 27/03 23:30 BST
     ('2022-03-27T23:30', date(2022, 3, 27), 1),  # 28/03 00:30 BST
     ('2022-03-26T23:30', date(2022, 3, 26), 1),  # 26/03 23:30 GMT
diff --git a/tests/app/dao/test_complaint_dao.py b/tests/app/dao/test_complaint_dao.py
index 290337fb9..af16b8af2 100644
--- a/tests/app/dao/test_complaint_dao.py
+++ b/tests/app/dao/test_complaint_dao.py
@@ -117,7 +117,7 @@ def test_fetch_count_of_complaints(sample_email_notification):
 
     count_of_complaints = fetch_count_of_complaints(start_date=datetime(2018, 6, 7),
                                                     end_date=datetime(2018, 6, 7))
-    assert count_of_complaints == 3
+    assert count_of_complaints == 5
 
 
 def test_fetch_count_of_complaints_returns_zero(notify_db_session):
diff --git a/tests/app/dao/test_date_utils.py b/tests/app/dao/test_date_utils.py
index f153c64d0..c09e18968 100644
--- a/tests/app/dao/test_date_utils.py
+++ b/tests/app/dao/test_date_utils.py
@@ -12,22 +12,22 @@
 
 def test_get_financial_year():
     start, end = get_financial_year(2000)
-    assert str(start) == '2000-04-01 05:00:00'
-    assert str(end) == '2001-04-01 04:59:59.999999'
+    assert str(start) == '2000-04-01 00:00:00'
+    assert str(end) == '2001-03-31 23:59:59.999999'
 
 
 def test_get_april_fools():
     april_fools = get_april_fools(2016)
-    assert str(april_fools) == '2016-04-01 04:00:00'
+    assert str(april_fools) == '2016-04-01 00:00:00'
     assert april_fools.tzinfo is None
 
 
 @pytest.mark.parametrize("month, year, expected_start, expected_end", [
-    (7, 2017, datetime(2017, 7, 1, 4, 00, 00), datetime(2017, 8, 1, 3, 59, 59, 99999)),
-    (2, 2016, datetime(2016, 2, 1, 5, 00, 00), datetime(2016, 3, 1, 4, 59, 59, 99999)),
-    (2, 2017, datetime(2017, 2, 1, 5, 00, 00), datetime(2017, 3, 1, 4, 59, 59, 99999)),
-    (9, 2018, datetime(2018, 9, 1, 4, 00, 00), datetime(2018, 10, 1, 3, 59, 59, 99999)),
-    (12, 2019, datetime(2019, 12, 1, 5, 00, 00), datetime(2020, 1, 1, 4, 59, 59, 99999))
+    (7, 2017, datetime(2017, 7, 1, 0, 00, 00), datetime(2017, 7, 31, 23, 59, 59, 99999)),
+    (2, 2016, datetime(2016, 2, 1, 0, 00, 00), datetime(2016, 2, 29, 23, 59, 59, 99999)),
+    (2, 2017, datetime(2017, 2, 1, 0, 00, 00), datetime(2017, 2, 28, 23, 59, 59, 99999)),
+    (9, 2018, datetime(2018, 9, 1, 0, 00, 00), datetime(2018, 9, 30, 23, 59, 59, 99999)),
+    (12, 2019, datetime(2019, 12, 1, 0, 00, 00), datetime(2019, 12, 31, 23, 59, 59, 99999))
 ])
 def test_get_month_start_and_end_date_in_utc(month, year, expected_start, expected_end):
     month_year = datetime(year, month, 10, 13, 30, 00)
@@ -37,11 +37,10 @@ def test_get_month_start_and_end_date_in_utc(month, year, expected_start, expect
 
 
 @pytest.mark.parametrize("dt, fy", [
-    (datetime(2018, 4, 1, 4, 0, 0), 2018),
-    (datetime(2019, 4, 1, 3, 59, 59), 2018),
-    (datetime(2019, 4, 1, 4, 0, 0), 2019),
+    (datetime(2018, 4, 1, 1, 0, 0), 2018),
+    (datetime(2019, 3, 31, 23, 59, 59), 2018),
     (date(2019, 3, 31), 2018),
-    (date(2019, 4, 2), 2019),  # date() gives midnight UTC, which is the day before in ET
+    (date(2019, 4, 2), 2019),
 ])
 def test_get_financial_year_for_datetime(dt, fy):
     assert get_financial_year_for_datetime(dt) == fy
diff --git a/tests/app/dao/test_fact_billing_dao.py b/tests/app/dao/test_fact_billing_dao.py
index edb4e3692..ecc71efa5 100644
--- a/tests/app/dao/test_fact_billing_dao.py
+++ b/tests/app/dao/test_fact_billing_dao.py
@@ -3,7 +3,6 @@
 
 import pytest
 from freezegun import freeze_time
-from notifications_utils.timezones import convert_utc_to_local_timezone
 
 from app import db
 from app.dao.fact_billing_dao import (
@@ -74,7 +73,7 @@ def test_fetch_billing_data_for_today_includes_data_with_the_right_key_type(noti
     for key_type in ['normal', 'test', 'team']:
         create_notification(template=template, status='delivered', key_type=key_type)
 
-    today = convert_utc_to_local_timezone(datetime.utcnow())
+    today = datetime.utcnow()
     results = fetch_billing_data_for_day(today.date())
     assert len(results) == 1
     assert results[0].notifications_sent == 2
@@ -87,7 +86,7 @@ def test_fetch_billing_data_for_day_only_calls_query_for_permission_type(notify_
     sms_template = create_template(service=service, template_type="sms")
     create_notification(template=email_template, status='delivered')
     create_notification(template=sms_template, status='delivered')
-    today = convert_utc_to_local_timezone(datetime.utcnow())
+    today = datetime.utcnow()
     results = fetch_billing_data_for_day(process_day=today.date(), check_permissions=True)
     assert len(results) == 1
 
@@ -99,7 +98,7 @@ def test_fetch_billing_data_for_day_only_calls_query_for_all_channels(notify_db_
     sms_template = create_template(service=service, template_type="sms")
     create_notification(template=email_template, status='delivered')
     create_notification(template=sms_template, status='delivered')
-    today = convert_utc_to_local_timezone(datetime.utcnow())
+    today = datetime.utcnow()
     results = fetch_billing_data_for_day(process_day=today.date(), check_permissions=False)
     assert len(results) == 2
 
@@ -115,10 +114,10 @@ def test_fetch_billing_data_for_today_includes_data_with_the_right_date(notify_d
     create_notification(template=template, status='delivered', created_at=datetime(2018, 4, 1, 0, 23, 23))
     create_notification(template=template, status='sending', created_at=process_day + timedelta(days=1))
 
-    day_under_test = convert_utc_to_local_timezone(process_day)
+    day_under_test = process_day
     results = fetch_billing_data_for_day(day_under_test.date())
     assert len(results) == 1
-    assert results[0].notifications_sent == 2
+    assert results[0].notifications_sent == 3
 
 
 def test_fetch_billing_data_for_day_is_grouped_by_template_and_notification_type(notify_db_session):
@@ -128,7 +127,7 @@ def test_fetch_billing_data_for_day_is_grouped_by_template_and_notification_type
     create_notification(template=email_template, status='delivered')
     create_notification(template=sms_template, status='delivered')
 
-    today = convert_utc_to_local_timezone(datetime.utcnow())
+    today = datetime.utcnow()
     results = fetch_billing_data_for_day(today.date())
     assert len(results) == 2
     assert results[0].notifications_sent == 1
@@ -143,7 +142,7 @@ def test_fetch_billing_data_for_day_is_grouped_by_service(notify_db_session):
     create_notification(template=email_template, status='delivered')
     create_notification(template=sms_template, status='delivered')
 
-    today = convert_utc_to_local_timezone(datetime.utcnow())
+    today = datetime.utcnow()
     results = fetch_billing_data_for_day(today.date())
     assert len(results) == 2
     assert results[0].notifications_sent == 1
@@ -156,7 +155,7 @@ def test_fetch_billing_data_for_day_is_grouped_by_provider(notify_db_session):
     create_notification(template=template, status='delivered', sent_by='sns')
     create_notification(template=template, status='delivered', sent_by='sns')
 
-    today = convert_utc_to_local_timezone(datetime.utcnow())
+    today = datetime.utcnow()
     results = fetch_billing_data_for_day(today.date())
     assert len(results) == 1
     assert results[0].notifications_sent == 2
@@ -169,7 +168,7 @@ def test_fetch_billing_data_for_day_is_grouped_by_rate_mulitplier(notify_db_sess
     create_notification(template=template, status='delivered', rate_multiplier=1)
     create_notification(template=template, status='delivered', rate_multiplier=2)
 
-    today = convert_utc_to_local_timezone(datetime.utcnow())
+    today = datetime.utcnow()
     results = fetch_billing_data_for_day(today.date())
     assert len(results) == 2
     assert results[0].notifications_sent == 1
@@ -182,7 +181,7 @@ def test_fetch_billing_data_for_day_is_grouped_by_international(notify_db_sessio
     create_notification(template=sms_template, status='delivered', international=True)
     create_notification(template=sms_template, status='delivered', international=False)
 
-    today = convert_utc_to_local_timezone(datetime.utcnow())
+    today = datetime.utcnow()
     results = fetch_billing_data_for_day(today.date())
     assert len(results) == 2
     assert all(result.notifications_sent == 1 for result in results)
@@ -198,7 +197,7 @@ def test_fetch_billing_data_for_day_is_grouped_by_notification_type(notify_db_se
     create_notification(template=email_template, status='delivered')
     create_notification(template=email_template, status='delivered')
 
-    today = convert_utc_to_local_timezone(datetime.utcnow())
+    today = datetime.utcnow()
     results = fetch_billing_data_for_day(today.date())
     assert len(results) == 2
     notification_types = [x.notification_type for x in results]
@@ -206,7 +205,7 @@ def test_fetch_billing_data_for_day_is_grouped_by_notification_type(notify_db_se
 
 
 def test_fetch_billing_data_for_day_returns_empty_list(notify_db_session):
-    today = convert_utc_to_local_timezone(datetime.utcnow())
+    today = datetime.utcnow()
     results = fetch_billing_data_for_day(today.date())
     assert results == []
 
@@ -239,7 +238,7 @@ def test_fetch_billing_data_for_day_returns_list_for_given_service(notify_db_ses
     create_notification(template=template, status='delivered')
     create_notification(template=template_2, status='delivered')
 
-    today = convert_utc_to_local_timezone(datetime.utcnow())
+    today = datetime.utcnow()
     results = fetch_billing_data_for_day(process_day=today.date(), service_id=service.id)
     assert len(results) == 1
     assert results[0].service_id == service.id
@@ -252,7 +251,7 @@ def test_fetch_billing_data_for_day_bills_correctly_for_status(notify_db_session
     for status in NOTIFICATION_STATUS_TYPES:
         create_notification(template=sms_template, status=status)
         create_notification(template=email_template, status=status)
-    today = convert_utc_to_local_timezone(datetime.utcnow())
+    today = datetime.utcnow()
     results = fetch_billing_data_for_day(process_day=today.date(), service_id=service.id)
 
     sms_results = [x for x in results if x.notification_type == 'sms']
diff --git a/tests/app/dao/test_inbound_sms_dao.py b/tests/app/dao/test_inbound_sms_dao.py
index 9f234bcbb..dfa2d6fc5 100644
--- a/tests/app/dao/test_inbound_sms_dao.py
+++ b/tests/app/dao/test_inbound_sms_dao.py
@@ -64,8 +64,8 @@ def test_get_all_inbound_sms_filters_on_service(notify_db_session):
 
 
 def test_get_all_inbound_sms_filters_on_time(sample_service, notify_db_session):
-    create_inbound_sms(sample_service, created_at=datetime(2017, 8, 7, 3, 59))  # sunday evening
-    sms_two = create_inbound_sms(sample_service, created_at=datetime(2017, 8, 7, 4, 0))  # monday (7th) morning
+    create_inbound_sms(sample_service, created_at=datetime(2017, 8, 6, 23, 59))  # sunday evening
+    sms_two = create_inbound_sms(sample_service, created_at=datetime(2017, 8, 7, 0, 0))  # monday (7th) morning
 
     with freeze_time('2017-08-14 12:00'):
         res = dao_get_inbound_sms_for_service(sample_service.id, limit_days=7)
@@ -87,9 +87,9 @@ def test_count_inbound_sms_for_service(notify_db_session):
 
 def test_count_inbound_sms_for_service_filters_messages_older_than_n_days(sample_service):
     # test between evening sunday 2nd of june and morning of monday 3rd
-    create_inbound_sms(sample_service, created_at=datetime(2019, 6, 3, 3, 59))
-    create_inbound_sms(sample_service, created_at=datetime(2019, 6, 3, 3, 59))
-    create_inbound_sms(sample_service, created_at=datetime(2019, 6, 3, 4, 1))
+    create_inbound_sms(sample_service, created_at=datetime(2019, 6, 2, 23, 59))
+    create_inbound_sms(sample_service, created_at=datetime(2019, 6, 2, 23, 59))
+    create_inbound_sms(sample_service, created_at=datetime(2019, 6, 3, 0, 1))
 
     with freeze_time('Monday 10th June 2019 12:00'):
         assert dao_count_inbound_sms_for_service(sample_service.id, limit_days=7) == 1
@@ -108,10 +108,10 @@ def test_should_delete_inbound_sms_according_to_data_retention(notify_db_session
     create_service_data_retention(short_retention_service, notification_type='email', days_of_retention=4)
 
     dates = [
-        datetime(2017, 6, 5, 4, 00),  # just before three days
-        datetime(2017, 6, 5, 3, 59),  # older than three days
-        datetime(2017, 6, 1, 4, 00),  # just before seven days
-        datetime(2017, 6, 1, 3, 59),  # older than seven days
+        datetime(2017, 6, 5, 0, 00),  # just before three days
+        datetime(2017, 6, 4, 23, 59),  # older than three days
+        datetime(2017, 6, 1, 0, 00),  # just before seven days
+        datetime(2017, 5, 31, 23, 59),  # older than seven days
         datetime(2017, 5, 1, 0, 0),  # older than thirty days
     ]
 
@@ -340,9 +340,9 @@ def test_most_recent_inbound_sms_paginates_properly(notify_api, sample_service):
 
 def test_most_recent_inbound_sms_only_returns_values_within_7_days(sample_service):
     # just out of bounds
-    create_inbound_sms(sample_service, user_number='1', content='old', created_at=datetime(2017, 4, 3, 3, 59, 59))
+    create_inbound_sms(sample_service, user_number='1', content='old', created_at=datetime(2017, 4, 2, 23, 59, 59))
     # just in bounds
-    create_inbound_sms(sample_service, user_number='2', content='new', created_at=datetime(2017, 4, 3, 4, 0, 0))
+    create_inbound_sms(sample_service, user_number='2', content='new', created_at=datetime(2017, 4, 3, 0, 0, 0))
 
     with freeze_time('Monday 10th April 2017 12:00:00'):
         res = dao_get_paginated_most_recent_inbound_sms_by_user_number_for_service(sample_service.id, limit_days=7, page=1)  # noqa
diff --git a/tests/app/dao/test_jobs_dao.py b/tests/app/dao/test_jobs_dao.py
index 335dece62..72e692945 100644
--- a/tests/app/dao/test_jobs_dao.py
+++ b/tests/app/dao/test_jobs_dao.py
@@ -136,8 +136,8 @@ def test_get_jobs_for_service_with_limit_days_param(sample_template):
 @freeze_time('2017-06-10')
 def test_get_jobs_for_service_with_limit_days_edge_case(sample_template):
     one_job = create_job(sample_template)
-    just_after_midnight_job = create_job(sample_template, created_at=datetime(2017, 6, 3, 4, 0, 1))
-    just_before_midnight_job = create_job(sample_template, created_at=datetime(2017, 6, 3, 3, 59, 0))
+    just_after_midnight_job = create_job(sample_template, created_at=datetime(2017, 6, 3, 0, 0, 1))
+    just_before_midnight_job = create_job(sample_template, created_at=datetime(2017, 6, 2, 23, 59, 0))
 
     jobs_limit_days = dao_get_jobs_by_service_id(one_job.service_id, limit_days=7).items
     assert len(jobs_limit_days) == 2
diff --git a/tests/app/dao/test_services_dao.py b/tests/app/dao/test_services_dao.py
index d6ec13c3f..5d13bf4a4 100644
--- a/tests/app/dao/test_services_dao.py
+++ b/tests/app/dao/test_services_dao.py
@@ -777,7 +777,7 @@ def test_dao_fetch_todays_stats_for_service_only_includes_today(notify_db_sessio
         stats = dao_fetch_todays_stats_for_service(template.service_id)
 
     stats = {row.status: row.count for row in stats}
-    assert 'delivered' not in stats
+    assert stats['delivered'] == 1
     assert stats['failed'] == 1
     assert stats['created'] == 1
 
@@ -807,7 +807,7 @@ def test_dao_fetch_todays_stats_for_service_only_includes_today_when_clocks_spri
 
 def test_dao_fetch_todays_stats_for_service_only_includes_today_during_bst(notify_db_session):
     template = create_template(service=create_service())
-    with freeze_time('2021-03-29T03:59:59'):
+    with freeze_time('2021-03-28T23:59:59'):
         # just before midnight BST -- not included
         create_notification(template=template, to_field='1', status='permanent-failure')
     with freeze_time('2021-03-29T04:00:01'):
diff --git a/tests/app/inbound_sms/test_rest.py b/tests/app/inbound_sms/test_rest.py
index 0b7cd71f2..7d6991652 100644
--- a/tests/app/inbound_sms/test_rest.py
+++ b/tests/app/inbound_sms/test_rest.py
@@ -97,8 +97,8 @@ def test_post_to_get_inbound_sms_allows_badly_formatted_number(admin_request, sa
 
 @freeze_time('Monday 10th April 2017 12:00')
 def test_post_to_get_most_recent_inbound_sms_for_service_limits_to_a_week(admin_request, sample_service):
-    create_inbound_sms(sample_service, created_at=datetime(2017, 4, 3, 3, 59))
-    returned_inbound = create_inbound_sms(sample_service, created_at=datetime(2017, 4, 3, 4, 30))
+    create_inbound_sms(sample_service, created_at=datetime(2017, 4, 2, 23, 59))
+    returned_inbound = create_inbound_sms(sample_service, created_at=datetime(2017, 4, 3, 0, 30))
 
     sms = admin_request.post('inbound_sms.post_inbound_sms_for_service', service_id=sample_service.id, _data={})
 
diff --git a/tests/app/job/test_rest.py b/tests/app/job/test_rest.py
index c75c498e6..cca576060 100644
--- a/tests/app/job/test_rest.py
+++ b/tests/app/job/test_rest.py
@@ -751,10 +751,10 @@ def test_get_all_notifications_for_job_returns_csv_format(admin_request, sample_
     }
 
 
-@freeze_time('2017-06-10 04:00')
+@freeze_time('2017-06-10 00:00')
 def test_get_jobs_should_retrieve_from_ft_notification_status_for_old_jobs(admin_request, sample_template):
     # it's the 10th today, so 3 days should include all of 7th, 8th, 9th, and some of 10th.
-    just_three_days_ago = datetime(2017, 6, 7, 3, 59, 59)
+    just_three_days_ago = datetime(2017, 6, 6, 23, 59, 59)
     not_quite_three_days_ago = just_three_days_ago + timedelta(seconds=1)
 
     job_1 = create_job(sample_template, created_at=just_three_days_ago, processing_started=just_three_days_ago)
diff --git a/tests/app/service/test_utils.py b/tests/app/service/test_utils.py
index b8f7cdd2a..1effd5308 100644
--- a/tests/app/service/test_utils.py
+++ b/tests/app/service/test_utils.py
@@ -4,7 +4,7 @@
 
 
 # see get_financial_year for conversion of financial years.
-@freeze_time("2017-04-01 03:59:59.999999")
+@freeze_time("2017-03-31 23:59:59.999999")
 def test_get_current_financial_year_start_year_before_march():
     current_fy = get_current_financial_year_start_year()
     assert current_fy == 2016
diff --git a/tests/app/test_model.py b/tests/app/test_model.py
index e68a35c27..6ea7f772f 100644
--- a/tests/app/test_model.py
+++ b/tests/app/test_model.py
@@ -124,14 +124,14 @@ def test_notification_for_csv_returns_formatted_status(
 
 
 @freeze_time("2017-03-26 23:01:53.321312")
-def test_notification_for_csv_returns_bst_correctly(sample_template):
+def test_notification_for_csv_returns_utc_correctly(sample_template):
     notification = create_notification(sample_template)
 
     serialized = notification.serialize_for_csv()
-    assert serialized['created_at'] == '2017-03-26 19:01:53'
+    assert serialized['created_at'] == '2017-03-26 23:01:53'
 
 
-def test_notification_personalisation_getter_returns_empty_dict_from_None():
+def test_notification_personalisation_getter_returns_empty_dict_from_none():
     noti = Notification()
     noti._personalisation = None
     assert noti.personalisation == {}
diff --git a/tests/app/test_utils.py b/tests/app/test_utils.py
index 840eff607..07e36a005 100644
--- a/tests/app/test_utils.py
+++ b/tests/app/test_utils.py
@@ -5,28 +5,28 @@
 
 from app.utils import (
     format_sequential_number,
-    get_local_midnight_in_utc,
     get_midnight_for_day_before,
+    get_midnight_in_utc,
     midnight_n_days_ago,
 )
 
 
 @pytest.mark.parametrize('date, expected_date', [
-    (datetime(2016, 1, 15, 0, 30), datetime(2016, 1, 15, 5, 0)),
-    (datetime(2016, 6, 15, 0, 0), datetime(2016, 6, 15, 4, 0)),
-    (datetime(2016, 9, 15, 11, 59), datetime(2016, 9, 15, 4, 0)),
+    (datetime(2016, 1, 15, 0, 30), datetime(2016, 1, 15, 0, 0)),
+    (datetime(2016, 6, 15, 0, 0), datetime(2016, 6, 15, 0, 0)),
+    (datetime(2016, 9, 15, 11, 59), datetime(2016, 9, 15, 0, 0)),
     # works for both dates and datetimes
-    (date(2016, 1, 15), datetime(2016, 1, 15, 5, 0)),
-    (date(2016, 6, 15), datetime(2016, 6, 15, 4, 0)),
+    (date(2016, 1, 15), datetime(2016, 1, 15, 0, 0)),
+    (date(2016, 6, 15), datetime(2016, 6, 15, 0, 0)),
 ])
-def test_get_local_midnight_in_utc_returns_expected_date(date, expected_date):
-    assert get_local_midnight_in_utc(date) == expected_date
+def test_get_midnight_in_utc_returns_expected_date(date, expected_date):
+    assert get_midnight_in_utc(date) == expected_date
 
 
 @pytest.mark.parametrize('date, expected_date', [
-    (datetime(2016, 1, 15, 0, 30), datetime(2016, 1, 14, 5, 0)),
-    (datetime(2016, 7, 15, 0, 0), datetime(2016, 7, 14, 4, 0)),
-    (datetime(2016, 8, 23, 11, 59), datetime(2016, 8, 22, 4, 0)),
+    (datetime(2016, 1, 15, 0, 30), datetime(2016, 1, 14, 0, 0)),
+    (datetime(2016, 7, 15, 0, 0), datetime(2016, 7, 14, 0, 0)),
+    (datetime(2016, 8, 23, 11, 59), datetime(2016, 8, 22, 0, 0)),
 ])
 def test_get_midnight_for_day_before_returns_expected_date(date, expected_date):
     assert get_midnight_for_day_before(date) == expected_date
@@ -34,20 +34,20 @@ def test_get_midnight_for_day_before_returns_expected_date(date, expected_date):
 
 @pytest.mark.parametrize('current_time, arg, expected_datetime', [
     # winter
-    ('2018-01-10 23:59', 1, datetime(2018, 1, 9, 5, 0)),
-    ('2018-01-11 00:00', 1, datetime(2018, 1, 10, 5, 0)),
+    ('2018-01-10 23:59', 1, datetime(2018, 1, 9, 0, 0)),
+    ('2018-01-11 00:00', 1, datetime(2018, 1, 10, 0, 0)),
 
     # bst switchover at 1am 25th
-    ('2018-03-25 10:00', 1, datetime(2018, 3, 24, 4, 0)),
-    ('2018-03-26 10:00', 1, datetime(2018, 3, 25, 4, 0)),
-    ('2018-03-27 10:00', 1, datetime(2018, 3, 26, 4, 0)),
+    ('2018-03-25 10:00', 1, datetime(2018, 3, 24, 0, 0)),
+    ('2018-03-26 10:00', 1, datetime(2018, 3, 25, 0, 0)),
+    ('2018-03-27 10:00', 1, datetime(2018, 3, 26, 0, 0)),
 
     # summer
-    ('2018-06-05 10:00', 1, datetime(2018, 6, 4, 4, 0)),
+    ('2018-06-05 10:00', 1, datetime(2018, 6, 4, 0, 0)),
 
     # zero days ago
-    ('2018-01-11 00:00', 0, datetime(2018, 1, 11, 5, 0)),
-    ('2018-06-05 10:00', 0, datetime(2018, 6, 5, 4, 0)),
+    ('2018-01-11 00:00', 0, datetime(2018, 1, 11, 0, 0)),
+    ('2018-06-05 10:00', 0, datetime(2018, 6, 5, 0, 0)),
 ])
 def test_midnight_n_days_ago(current_time, arg, expected_datetime):
     with freeze_time(current_time):

From 3b0d38ea39823f067cd0149b4ba7df7ab9aa43c5 Mon Sep 17 00:00:00 2001
From: Kenneth Kehl <@kkehl@flexion.us>
Date: Tue, 30 May 2023 12:16:49 -0700
Subject: [PATCH 2/6] more fix

---
 app/dao/fact_notification_status_dao.py | 4 ++--
 app/utils.py                            | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/app/dao/fact_notification_status_dao.py b/app/dao/fact_notification_status_dao.py
index aa884cc2d..923ad9ad0 100644
--- a/app/dao/fact_notification_status_dao.py
+++ b/app/dao/fact_notification_status_dao.py
@@ -28,8 +28,8 @@
     Template,
 )
 from app.utils import (
-    get_local_month_from_utc_column,
     get_midnight_in_utc,
+    get_month_from_utc_column,
     midnight_n_days_ago,
 )
 
@@ -358,7 +358,7 @@ def fetch_monthly_template_usage_for_service(start_date, end_date, service_id):
 
     if start_date <= datetime.utcnow() <= end_date:
         today = get_midnight_in_utc(datetime.utcnow())
-        month = get_local_month_from_utc_column(Notification.created_at)
+        month = get_month_from_utc_column(Notification.created_at)
 
         stats_for_today = db.session.query(
             Notification.template_id.label('template_id'),
diff --git a/app/utils.py b/app/utils.py
index 622582997..97cc01673 100644
--- a/app/utils.py
+++ b/app/utils.py
@@ -63,7 +63,7 @@ def get_midnight_for_day_before(date):
     return get_midnight_in_utc(day_before)
 
 
-def get_local_month_from_utc_column(column):
+def get_month_from_utc_column(column):
     """
      Where queries need to count notifications by month it needs to be
      the month in local time.
@@ -75,7 +75,7 @@ def get_local_month_from_utc_column(column):
     """
     return func.date_trunc(
         "month",
-        func.timezone(getenv("TIMEZONE", "America/New_York"), func.timezone("UTC", column))
+        func.timezone(getenv("TIMEZONE", "UTC"), func.timezone("UTC", column))
     )
 
 

From db0d82923890dd4f96f5146cac5456ee69a07cf5 Mon Sep 17 00:00:00 2001
From: Kenneth Kehl <@kkehl@flexion.us>
Date: Wed, 31 May 2023 17:52:16 -0700
Subject: [PATCH 3/6] notify-281 fix time-sensitive tests

---
 app/dao/services_dao.py                  | 3 ++-
 app/service/rest.py                      | 1 -
 tests/app/celery/test_reporting_tasks.py | 2 +-
 tests/app/db.py                          | 1 -
 tests/app/template/test_rest_history.py  | 5 +++--
 5 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/app/dao/services_dao.py b/app/dao/services_dao.py
index 4456d32b2..ea5035a8a 100644
--- a/app/dao/services_dao.py
+++ b/app/dao/services_dao.py
@@ -404,10 +404,11 @@ def dao_fetch_todays_stats_for_service(service_id):
 
 
 def dao_fetch_todays_stats_for_all_services(include_from_test_key=True, only_active=True):
-    today = date.today()
+    today = datetime.utcnow().date()
     start_date = get_midnight_in_utc(today)
     end_date = get_midnight_in_utc(today + timedelta(days=1))
 
+
     subquery = db.session.query(
         Notification.notification_type,
         Notification.status,
diff --git a/app/service/rest.py b/app/service/rest.py
index abeb41e48..43d3ec63a 100644
--- a/app/service/rest.py
+++ b/app/service/rest.py
@@ -527,7 +527,6 @@ def get_detailed_services(start_date, end_date, only_active=False, include_from_
         stats = dao_fetch_todays_stats_for_all_services(include_from_test_key=include_from_test_key,
                                                         only_active=only_active)
     else:
-
         stats = fetch_stats_for_all_services_by_date_range(start_date=start_date,
                                                            end_date=end_date,
                                                            include_from_test_key=include_from_test_key,
diff --git a/tests/app/celery/test_reporting_tasks.py b/tests/app/celery/test_reporting_tasks.py
index d0d6c4e3e..cbbbdefbf 100644
--- a/tests/app/celery/test_reporting_tasks.py
+++ b/tests/app/celery/test_reporting_tasks.py
@@ -495,7 +495,7 @@ def test_create_nightly_notification_status_for_service_and_day(notify_db_sessio
 def test_create_nightly_notification_status_for_service_and_day_overwrites_old_data(notify_db_session):
     first_service = create_service(service_name='First Service')
     first_template = create_template(service=first_service)
-    process_day = date.today()
+    process_day = datetime.utcnow().date()
 
     # first run: one notification, expect one row (just one status)
     notification = create_notification(template=first_template, status='sending')
diff --git a/tests/app/db.py b/tests/app/db.py
index 92320a862..30023f437 100644
--- a/tests/app/db.py
+++ b/tests/app/db.py
@@ -297,7 +297,6 @@ def create_notification(
     }
     notification = Notification(**data)
     dao_create_notification(notification)
-
     return notification
 
 
diff --git a/tests/app/template/test_rest_history.py b/tests/app/template/test_rest_history.py
index 3e6f400d2..8f8b82ef2 100644
--- a/tests/app/template/test_rest_history.py
+++ b/tests/app/template/test_rest_history.py
@@ -1,5 +1,5 @@
 import json
-from datetime import date, datetime
+from datetime import datetime
 
 from flask import url_for
 
@@ -27,7 +27,8 @@ def test_template_history_version(notify_api, sample_user, sample_template):
             assert json_resp['data']['version'] == 1
             assert json_resp['data']['process_type'] == 'normal'
             assert json_resp['data']['created_by']['name'] == sample_user.name
-            assert datetime.strptime(json_resp['data']['created_at'], '%Y-%m-%d %H:%M:%S.%f').date() == date.today()
+            assert datetime.strptime(json_resp['data']['created_at'], '%Y-%m-%d %H:%M:%S.%f').date() == \
+                   datetime.utcnow().date()
 
 
 def test_previous_template_history_version(notify_api, sample_template):

From 38461af5ae8c94bad6460575c17f1efff196a04d Mon Sep 17 00:00:00 2001
From: Kenneth Kehl <@kkehl@flexion.us>
Date: Wed, 31 May 2023 17:57:24 -0700
Subject: [PATCH 4/6] fix format

---
 app/dao/services_dao.py | 1 -
 1 file changed, 1 deletion(-)

diff --git a/app/dao/services_dao.py b/app/dao/services_dao.py
index ea5035a8a..793211d80 100644
--- a/app/dao/services_dao.py
+++ b/app/dao/services_dao.py
@@ -408,7 +408,6 @@ def dao_fetch_todays_stats_for_all_services(include_from_test_key=True, only_act
     start_date = get_midnight_in_utc(today)
     end_date = get_midnight_in_utc(today + timedelta(days=1))
 
-
     subquery = db.session.query(
         Notification.notification_type,
         Notification.status,

From 80c6c677db95c7f775407253616d42d152ab1f12 Mon Sep 17 00:00:00 2001
From: Kenneth Kehl <@kkehl@flexion.us>
Date: Wed, 31 May 2023 10:07:27 -0700
Subject: [PATCH 5/6] clean up remaining todays()

---
 app/dao/services_dao.py                    | 4 ++--
 tests/app/celery/test_reporting_tasks.py   | 4 ++--
 tests/app/complaint/test_complaint_rest.py | 4 ++--
 tests/app/dao/test_fact_billing_dao.py     | 2 +-
 4 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/app/dao/services_dao.py b/app/dao/services_dao.py
index 793211d80..2c1d9a381 100644
--- a/app/dao/services_dao.py
+++ b/app/dao/services_dao.py
@@ -1,5 +1,5 @@
 import uuid
-from datetime import date, datetime, timedelta
+from datetime import datetime, timedelta
 
 from flask import current_app
 from sqlalchemy import Float, cast
@@ -387,7 +387,7 @@ def _delete_commit(query):
 
 
 def dao_fetch_todays_stats_for_service(service_id):
-    today = date.today()
+    today = datetime.utcnow().date()
     start_date = get_midnight_in_utc(today)
     return db.session.query(
         Notification.notification_type,
diff --git a/tests/app/celery/test_reporting_tasks.py b/tests/app/celery/test_reporting_tasks.py
index cbbbdefbf..f2dc6b549 100644
--- a/tests/app/celery/test_reporting_tasks.py
+++ b/tests/app/celery/test_reporting_tasks.py
@@ -426,7 +426,7 @@ def test_create_nightly_notification_status_for_service_and_day(notify_db_sessio
     second_service = create_service(service_name='second Service')
     second_template = create_template(service=second_service, template_type='email')
 
-    process_day = date.today() - timedelta(days=5)
+    process_day = datetime.utcnow().date() - timedelta(days=5)
     with freeze_time(datetime.combine(process_day, time.max)):
         create_notification(template=first_template, status='delivered')
         create_notification(template=second_template, status='temporary-failure')
@@ -441,7 +441,7 @@ def test_create_nightly_notification_status_for_service_and_day(notify_db_sessio
         create_notification_history(template=second_template, status='delivered')
 
     # these created notifications from a different day get ignored
-    with freeze_time(datetime.combine(date.today() - timedelta(days=4), time.max)):
+    with freeze_time(datetime.combine(datetime.utcnow().date() - timedelta(days=4), time.max)):
         create_notification(template=first_template)
         create_notification_history(template=second_template)
 
diff --git a/tests/app/complaint/test_complaint_rest.py b/tests/app/complaint/test_complaint_rest.py
index 5f72e4ee2..9dd5aca06 100644
--- a/tests/app/complaint/test_complaint_rest.py
+++ b/tests/app/complaint/test_complaint_rest.py
@@ -1,5 +1,5 @@
 import json
-from datetime import date
+from datetime import date, datetime
 
 from flask import url_for
 from freezegun import freeze_time
@@ -74,7 +74,7 @@ def test_get_complaint_sets_start_and_end_date_to_today_if_not_specified(mocker,
     dao_mock = mocker.patch('app.complaint.complaint_rest.fetch_count_of_complaints', return_value=5)
     response = client.get(url_for('complaint.get_complaint_count'), headers=[create_admin_authorization_header()])
 
-    dao_mock.assert_called_once_with(start_date=date.today(), end_date=date.today())
+    dao_mock.assert_called_once_with(start_date=datetime.utcnow().date(), end_date=datetime.utcnow().date())
     assert response.status_code == 200
     assert json.loads(response.get_data(as_text=True)) == 5
 
diff --git a/tests/app/dao/test_fact_billing_dao.py b/tests/app/dao/test_fact_billing_dao.py
index e900c0cbe..4edd7a533 100644
--- a/tests/app/dao/test_fact_billing_dao.py
+++ b/tests/app/dao/test_fact_billing_dao.py
@@ -714,7 +714,7 @@ def test_fetch_usage_year_for_organisation_only_queries_present_year(notify_db_s
     last_year = current_year - 1
     date_two_years_ago = date(2021, 3, 31)
     date_in_last_financial_year = date(2022, 3, 31)
-    date_in_this_year = date.today()
+    date_in_this_year = datetime.utcnow().date()
 
     org = create_organisation(name='Organisation 1')
 

From 15a70460bc38d057555675c5e7f84fa3c2a7970a Mon Sep 17 00:00:00 2001
From: Kenneth Kehl <@kkehl@flexion.us>
Date: Thu, 1 Jun 2023 07:07:10 -0700
Subject: [PATCH 6/6] code review feedback

---
 app/dao/fact_notification_status_dao.py | 8 ++++----
 app/utils.py                            | 3 +--
 2 files changed, 5 insertions(+), 6 deletions(-)

diff --git a/app/dao/fact_notification_status_dao.py b/app/dao/fact_notification_status_dao.py
index 923ad9ad0..857256cd3 100644
--- a/app/dao/fact_notification_status_dao.py
+++ b/app/dao/fact_notification_status_dao.py
@@ -104,16 +104,16 @@ def fetch_notification_status_for_service_by_month(start_date, end_date, service
     ).all()
 
 
-def fetch_notification_status_for_service_for_day(bst_day, service_id):
+def fetch_notification_status_for_service_for_day(fetch_day, service_id):
     return db.session.query(
         # return current month as a datetime so the data has the same shape as the ft_notification_status query
-        literal(bst_day.replace(day=1), type_=DateTime).label('month'),
+        literal(fetch_day.replace(day=1), type_=DateTime).label('month'),
         Notification.notification_type,
         Notification.status.label('notification_status'),
         func.count().label('count')
     ).filter(
-        Notification.created_at >= get_midnight_in_utc(bst_day),
-        Notification.created_at < get_midnight_in_utc(bst_day + timedelta(days=1)),
+        Notification.created_at >= get_midnight_in_utc(fetch_day),
+        Notification.created_at < get_midnight_in_utc(fetch_day + timedelta(days=1)),
         Notification.service_id == service_id,
         Notification.key_type != KEY_TYPE_TEST
     ).group_by(
diff --git a/app/utils.py b/app/utils.py
index 97cc01673..94d4ac576 100644
--- a/app/utils.py
+++ b/app/utils.py
@@ -1,5 +1,4 @@
 from datetime import datetime, timedelta
-from os import getenv
 
 from flask import url_for
 from notifications_utils.template import HTMLEmailTemplate, SMSMessageTemplate
@@ -75,7 +74,7 @@ def get_month_from_utc_column(column):
     """
     return func.date_trunc(
         "month",
-        func.timezone(getenv("TIMEZONE", "UTC"), func.timezone("UTC", column))
+        func.timezone("UTC", func.timezone("UTC", column))
     )