Remove unused method.

last_n_days was only being used in a test.

app/celery/reporting_tasks.py

@@ -2,6 +2,7 @@ from datetime import datetime, timedelta
 
 from flask import current_app
 from notifications_utils.statsd_decorators import statsd
+from notifications_utils.timezones import convert_utc_to_bst
 
 from app import notify_celery
 from app.cronitor import cronitor
@@ -10,7 +11,6 @@ from app.dao.fact_billing_dao import (
     update_fact_billing
 )
 from app.dao.fact_notification_status_dao import fetch_notification_status_for_day, update_fact_notification_status
-from app.utils import convert_utc_to_bst
 
 
 @notify_celery.task(name="create-nightly-billing")

app/utils.py

@@ -4,7 +4,6 @@ import pytz
 from flask import url_for
 from sqlalchemy import func
 from notifications_utils.template import SMSMessageTemplate, WithSubjectTemplate, get_html_email_body
-from notifications_utils.timezones import convert_utc_to_bst
 
 local_timezone = pytz.timezone("Europe/London")
 
@@ -100,21 +99,6 @@ def midnight_n_days_ago(number_of_days):
     return get_london_midnight_in_utc(datetime.utcnow() - timedelta(days=number_of_days))
 
 
-def last_n_days(limit_days):
-    """
-    Returns the last n dates, oldest first. Takes care of daylight savings (but returns a date, be careful how you
-    manipulate it later! Don't directly use the date for comparing to UTC datetimes!). Includes today.
-    """
-    return [
-        datetime.combine(
-            (convert_utc_to_bst(datetime.utcnow()) - timedelta(days=x)),
-            datetime.min.time()
-        )
-        # reverse the countdown, -1 from first two args to ensure it stays 0-indexed
-        for x in range(limit_days - 1, -1, -1)
-    ]
-
-
 def escape_special_characters(string):
     for special_character in ('\\', '_', '%', '/'):
         string = string.replace(

tests/app/test_utils.py

@@ -7,7 +7,6 @@ from app.utils import (
     get_london_midnight_in_utc,
     get_midnight_for_day_before,
     midnight_n_days_ago,
-    last_n_days
 )
 
 
@@ -52,21 +51,3 @@ def test_get_midnight_for_day_before_returns_expected_date(date, expected_date):
 def test_midnight_n_days_ago(current_time, arg, expected_datetime):
     with freeze_time(current_time):
         assert midnight_n_days_ago(arg) == expected_datetime
-
-
-def test_last_n_days():
-    with freeze_time('2018-03-27 12:00'):
-        res = last_n_days(5)
-
-    assert res == [
-        datetime(2018, 3, 23, 0, 0),
-        datetime(2018, 3, 24, 0, 0),
-        datetime(2018, 3, 25, 0, 0),
-        datetime(2018, 3, 26, 0, 0),
-        datetime(2018, 3, 27, 0, 0)
-    ]
-
-
-@pytest.mark.parametrize('arg', [0, -1])
-def test_last_n_days_invalid_arg(arg):
-    assert last_n_days(arg) == []