Migration to add international letter rates

New rows giving the prices of letters with a post_class of `europe` and
`rest-of-world` have been added to the `letter_rates` table. All rates
are currently the same for international letters.

migrations/versions/0324_int_letter_rates.py

@@ -0,0 +1,54 @@
+"""
+
+Revision ID: 0324_int_letter_rates
+Revises: 0323_broadcast_message
+Create Date: 2020-07-08 12:20:20.700128
+
+"""
+import itertools
+import uuid
+from datetime import datetime
+
+from alembic import op
+from sqlalchemy.sql import text
+
+from app.models import LetterRate
+
+
+revision = '0324_int_letter_rates'
+down_revision = '0323_broadcast_message'
+
+base_rate = 76
+start_date = datetime(2020, 7, 1, 0, 0)
+
+
+def upgrade():
+    """
+    Insert these letter rates for a post_class of both `europe` and `rest-of-world`:
+    1 sheet - £0.84
+    2 sheets - £0.92
+    3 sheets - £1.00
+    4 sheets - £1.08
+    5 sheets - £1.16
+    """
+    op.bulk_insert(LetterRate.__table__, [
+        {
+            'id': uuid.uuid4(),
+            'start_date': start_date,
+            'end_date': None,
+            'sheet_count': sheet_count,
+            'rate': (base_rate + (8 * sheet_count)) / 100.0,
+            'crown': crown,
+            'post_class': post_class,
+        }
+        for sheet_count, crown, post_class in itertools.product(
+            range(1, 6),
+            [True, False],
+            ['europe', 'rest-of-world']
+        )
+    ])
+
+
+def downgrade():
+    conn = op.get_bind()
+    conn.execute(text("DELETE FROM letter_rates WHERE start_date = :start"), start=start_date)

tests/app/celery/test_reporting_tasks.py

@@ -243,6 +243,22 @@ def test_create_nightly_billing_for_day_different_letter_postage(
         billable_units=2,
         postage='second'
     )
+    create_notification(
+        created_at=yesterday,
+        template=sample_letter_template,
+        status='delivered',
+        sent_by='dvla',
+        billable_units=1,
+        postage='europe'
+    )
+    create_notification(
+        created_at=yesterday,
+        template=sample_letter_template,
+        status='delivered',
+        sent_by='dvla',
+        billable_units=3,
+        postage='rest-of-world'
+    )
 
     records = FactBilling.query.all()
     assert len(records) == 0
@@ -251,18 +267,31 @@ def test_create_nightly_billing_for_day_different_letter_postage(
     create_nightly_billing_for_day(yesterday_str)
 
     records = FactBilling.query.order_by('postage').all()
-    assert len(records) == 2
+    assert len(records) == 4
+
     assert records[0].notification_type == LETTER_TYPE
     assert records[0].bst_date == datetime.date(yesterday)
-    assert records[0].postage == 'first'
-    assert records[0].notifications_sent == 2
-    assert records[0].billable_units == 4
+    assert records[0].postage == 'europe'
+    assert records[0].notifications_sent == 1
+    assert records[0].billable_units == 1
 
     assert records[1].notification_type == LETTER_TYPE
     assert records[1].bst_date == datetime.date(yesterday)
-    assert records[1].postage == 'second'
-    assert records[1].notifications_sent == 1
-    assert records[1].billable_units == 2
+    assert records[1].postage == 'first'
+    assert records[1].notifications_sent == 2
+    assert records[1].billable_units == 4
+
+    assert records[2].notification_type == LETTER_TYPE
+    assert records[2].bst_date == datetime.date(yesterday)
+    assert records[2].postage == 'rest-of-world'
+    assert records[2].notifications_sent == 1
+    assert records[2].billable_units == 3
+
+    assert records[3].notification_type == LETTER_TYPE
+    assert records[3].bst_date == datetime.date(yesterday)
+    assert records[3].postage == 'second'
+    assert records[3].notifications_sent == 1
+    assert records[3].billable_units == 2
 
 
 def test_create_nightly_billing_for_day_letter(

tests/app/dao/test_ft_billing_dao.py

@@ -326,10 +326,12 @@ def test_get_rates_for_billing(notify_db_session):
     create_rate(start_date=datetime.utcnow(), value=33, notification_type='email')
     create_letter_rate(start_date=datetime.utcnow(), rate=0.66, post_class='first')
     create_letter_rate(start_date=datetime.utcnow(), rate=0.33, post_class='second')
+    create_letter_rate(start_date=datetime.utcnow(), rate=0.84, post_class='europe')
+    create_letter_rate(start_date=datetime.utcnow(), rate=0.84, post_class='rest-of-world')
     non_letter_rates, letter_rates = get_rates_for_billing()
 
     assert len(non_letter_rates) == 3
-    assert len(letter_rates) == 2
+    assert len(letter_rates) == 4
 
 
 @freeze_time('2017-06-01 12:00')
@@ -353,10 +355,17 @@ def test_get_rate(notify_db_session):
     assert letter_rate == Decimal('0.3')
 
 
-@pytest.mark.parametrize("letter_post_class,expected_rate", [("first", "0.61"), ("second", "0.35")])
+@pytest.mark.parametrize("letter_post_class,expected_rate", [
+    ("first", "0.61"),
+    ("second", "0.35"),
+    ("europe", "0.92"),
+    ("rest-of-world", "1.05"),
+])
 def test_get_rate_filters_letters_by_post_class(notify_db_session, letter_post_class, expected_rate):
     create_letter_rate(start_date=datetime(2017, 5, 30, 23, 0), sheet_count=2, rate=0.61, post_class='first')
     create_letter_rate(start_date=datetime(2017, 5, 30, 23, 0), sheet_count=2, rate=0.35, post_class='second')
+    create_letter_rate(start_date=datetime(2017, 5, 30, 23, 0), sheet_count=2, rate=0.92, post_class='europe')
+    create_letter_rate(start_date=datetime(2017, 5, 30, 23, 0), sheet_count=2, rate=1.05, post_class='rest-of-world')
 
     non_letter_rates, letter_rates = get_rates_for_billing()
     rate = get_rate(non_letter_rates, letter_rates, "letter", datetime(2018, 10, 1), True, 2, letter_post_class)