Update letter data for usage-for-all-services report

Usage for all services is a platform admin report that groups letters by
postage. We want it to show `europe` and `rest-of-world` letters under a
single category of `international`, so this updates the query to do
that and to order appropriately.

tests/app/dao/test_ft_billing_dao.py

@@ -623,7 +623,7 @@ def test_fetch_letter_costs_for_all_services(notify_db_session):
     assert len(results) == 3
     assert results[0] == (org.name, org.id, service.name, service.id, Decimal('3.40'))
     assert results[1] == (org_2.name, org_2.id, service_2.name, service_2.id, Decimal('14.00'))
-    assert results[2] == (None, None, service_3.name, service_3.id, Decimal('8.25'))
+    assert results[2] == (None, None, service_3.name, service_3.id, Decimal('24.45'))
 
 
 def test_fetch_letter_line_items_for_all_service(notify_db_session):
@@ -632,12 +632,14 @@ def test_fetch_letter_line_items_for_all_service(notify_db_session):
 
     results = fetch_letter_line_items_for_all_services(datetime(2019, 6, 1), datetime(2019, 9, 30))
 
-    assert len(results) == 5
+    assert len(results) == 7
     assert results[0] == (org_1.name, org_1.id, service_1.name, service_1.id, Decimal('0.45'), 'second', 6)
     assert results[1] == (org_1.name, org_1.id, service_1.name, service_1.id, Decimal("0.35"), 'first', 2)
     assert results[2] == (org_2.name, org_2.id, service_2.name, service_2.id, Decimal("0.65"), 'second', 20)
     assert results[3] == (org_2.name, org_2.id, service_2.name, service_2.id, Decimal("0.50"), 'first', 2)
-    assert results[4] == (None, None, service_3.name, service_3.id, Decimal("0.55"), 'second', 15)
+    assert results[4] == (None, None, service_3.name, service_3.id, Decimal("0.35"), 'second', 2)
+    assert results[5] == (None, None, service_3.name, service_3.id, Decimal("0.50"), 'first', 1)
+    assert results[6] == (None, None, service_3.name, service_3.id, Decimal("1.55"), 'international', 15)
 
 
 @freeze_time('2019-06-01 13:30')

tests/app/db.py

@@ -941,7 +941,13 @@ def set_up_usage_data(start_date):
                       notifications_sent=12, billable_unit=5, rate=.65, postage='second')
 
     create_ft_billing(bst_date=two_days_later, template=letter_template_4,
-                      notifications_sent=15, billable_unit=4, rate=.55, postage='second')
+                      notifications_sent=7, billable_unit=4, rate=1.55, postage='rest-of-world')
+    create_ft_billing(bst_date=two_days_later, template=letter_template_4,
+                      notifications_sent=8, billable_unit=4, rate=1.55, postage='europe')
+    create_ft_billing(bst_date=two_days_later, template=letter_template_4,
+                      notifications_sent=2, billable_unit=1, rate=.35, postage='second')
+    create_ft_billing(bst_date=two_days_later, template=letter_template_4,
+                      notifications_sent=1, billable_unit=1, rate=.50, postage='first')
 
     create_ft_billing(bst_date=start_date, template=email_template, notifications_sent=10)
 

tests/app/platform_stats/test_rest.py

@@ -153,5 +153,7 @@ def test_get_usage_for_all_services(notify_db_session, admin_request):
     assert response[3]["service_id"] == str(service_3.id)
     assert response[3]["sms_cost"] == 0
     assert response[3]["sms_fragments"] == 0
-    assert response[3]["letter_cost"] == 8.25
-    assert response[3]["letter_breakdown"] == "15 second class letters at 55p\n"
+    assert response[3]["letter_cost"] == 24.45
+    assert response[3]["letter_breakdown"] == (
+        "2 second class letters at 35p\n1 first class letters at 50p\n15 international letters at £1.55\n"
+    )