make tests run consistently

* tests on API endpoints that we do not explicitly sort should
  either sort the results or compare results in an orderless way
  (e.g. converting to a set)
* tests that touch the provider_details should reset values after
  running, since the provider_details table is not torn down and
  re-created between tests (unlike most tables)

tests/app/notifications/test_rest.py

@@ -4,6 +4,7 @@ import uuid
 import pytest
 from flask import json
 from notifications_python_client.authentication import create_jwt_token
+from freezegun import freeze_time
 
 from app.dao.notifications_dao import dao_update_notification
 from app.dao.api_key_dao import save_model_api_key
@@ -584,19 +585,19 @@ def test_get_notifications_for_service_returns_merged_template_content(notify_ap
                                                                        notify_db,
                                                                        notify_db_session,
                                                                        sample_template_with_placeholders):
+    with freeze_time('2001-01-01T12:00:00'):
+        create_sample_notification(notify_db,
+                                   notify_db_session,
+                                   service=sample_template_with_placeholders.service,
+                                   template=sample_template_with_placeholders,
+                                   personalisation={"name": "merged with first"})
 
-    create_sample_notification(notify_db,
+    with freeze_time('2001-01-01T12:00:01'):
-                               notify_db_session,
+        create_sample_notification(notify_db,
-                               service=sample_template_with_placeholders.service,
+                                   notify_db_session,
-                               template=sample_template_with_placeholders,
+                                   service=sample_template_with_placeholders.service,
-                               personalisation={"name": "merged with first"},
+                                   template=sample_template_with_placeholders,
-                               created_at=datetime.utcnow() - timedelta(seconds=1))
+                                   personalisation={"name": "merged with second"})
-
-    create_sample_notification(notify_db,
-                               notify_db_session,
-                               service=sample_template_with_placeholders.service,
-                               template=sample_template_with_placeholders,
-                               personalisation={"name": "merged with second"})
 
     with notify_api.test_request_context():
         with notify_api.test_client() as client:
@@ -608,10 +609,10 @@ def test_get_notifications_for_service_returns_merged_template_content(notify_ap
                 headers=[auth_header])
             assert response.status_code == 200
 
-            resp = json.loads(response.get_data(as_text=True))
+            assert {noti['body'] for noti in json.loads(response.get_data(as_text=True))['notifications']} == {
-            assert len(resp['notifications']) == 2
+                'Hello merged with first\nYour thing is due soon',
-            assert resp['notifications'][0]['body'] == 'Hello merged with first\nYour thing is due soon'
+                'Hello merged with second\nYour thing is due soon'
-            assert resp['notifications'][1]['body'] == 'Hello merged with second\nYour thing is due soon'
+            }
 
 
 def _create_auth_header_from_key(api_key):

tests/app/provider_details/test_rest.py

@@ -70,13 +70,22 @@ def test_should_be_able_to_update_priority(notify_db, notify_db_session, notify_
                 '/provider-details/{}'.format(provider_id),
                 headers=[('Content-Type', 'application/json'), auth_header],
                 data=json.dumps({
-                    'priority': 10
+                    'priority': 5
                 })
             )
             assert update_resp.status_code == 200
             update_json = json.loads(update_resp.get_data(as_text=True))['provider_details']
             assert update_json['identifier'] == 'firetext'
-            assert update_json['priority'] == 10
+            assert update_json['priority'] == 5
+
+            update_resp = client.post(
+                '/provider-details/{}'.format(provider_id),
+                headers=[('Content-Type', 'application/json'), auth_header],
+                data=json.dumps({
+                    'priority': 20
+                })
+            )
+            assert update_resp.status_code == 200
 
 
 def test_should_be_able_to_update_status(notify_db, notify_db_session, notify_api):
@@ -89,10 +98,10 @@ def test_should_be_able_to_update_status(notify_db, notify_db_session, notify_ap
             )
             fetch_resp = json.loads(response.get_data(as_text=True))['provider_details']
 
-            provider_id = fetch_resp[2]['id']
+            firetext = next(x for x in fetch_resp if x['identifier'] == 'firetext')
 
             update_resp_1 = client.post(
-                '/provider-details/{}'.format(provider_id),
+                '/provider-details/{}'.format(firetext['id']),
                 headers=[('Content-Type', 'application/json'), auth_header],
                 data=json.dumps({
                     'active': False
@@ -104,7 +113,7 @@ def test_should_be_able_to_update_status(notify_db, notify_db_session, notify_ap
             assert not update_resp_1['active']
 
             update_resp_2 = client.post(
-                '/provider-details/{}'.format(provider_id),
+                '/provider-details/{}'.format(firetext['id']),
                 headers=[('Content-Type', 'application/json'), auth_header],
                 data=json.dumps({
                     'active': True