Implement notifications for admin users (#700)

* First stab at notification settings

* Add "global" setting for notification levels

* Trigger notification task

* Get users with permission for event

* Actually send notification emails

* More notifications

* Allow to turn off notifications

* Link in email to pause all notifications

* Add NotificationType to wordlist

* Add notification tests

* Add documentation

* Rebase fixes

src/tests/base/test_notifications.py

@@ -0,0 +1,118 @@
+from datetime import timedelta
+from decimal import Decimal
+
+import pytest
+from django.core import mail as djmail
+from django.db import transaction
+from django.utils.timezone import now
+
+from pretix.base.models import (
+    Event, Item, Order, OrderPosition, Organizer, User,
+)
+
+
+@pytest.fixture
+def event():
+    o = Organizer.objects.create(name='Dummy', slug='dummy')
+    event = Event.objects.create(
+        organizer=o, name='Dummy', slug='dummy',
+        date_from=now()
+    )
+    return event
+
+
+@pytest.fixture
+def order(event):
+    o = Order.objects.create(
+        code='FOO', event=event, email='dummy@dummy.test',
+        status=Order.STATUS_PENDING, locale='en',
+        datetime=now(), expires=now() + timedelta(days=10),
+        total=Decimal('46.00'), payment_provider='banktransfer'
+    )
+    tr19 = event.tax_rules.create(rate=Decimal('19.00'))
+    ticket = Item.objects.create(event=event, name='Early-bird ticket', tax_rule=tr19,
+                                 default_price=Decimal('23.00'), admission=True)
+    OrderPosition.objects.create(
+        order=o, item=ticket, variation=None,
+        price=Decimal("23.00"), attendee_name="Peter", positionid=1
+    )
+    return o
+
+
+@pytest.fixture
+def team(event):
+    return event.organizer.teams.create(all_events=True, can_view_orders=True)
+
+
+@pytest.fixture
+def user(team):
+    user = User.objects.create_user('dummy@dummy.dummy', 'dummy')
+    team.members.add(user)
+    return user
+
+
+@pytest.fixture
+def monkeypatch_on_commit(monkeypatch):
+    monkeypatch.setattr("django.db.transaction.on_commit", lambda t: t())
+
+
+@pytest.mark.django_db
+def test_notification_trigger_event_specific(event, order, user, monkeypatch_on_commit):
+    djmail.outbox = []
+    user.notification_settings.create(
+        method='mail', event=event, action_type='pretix.event.order.paid', enabled=True
+    )
+    with transaction.atomic():
+        order.log_action('pretix.event.order.paid', {})
+    assert len(djmail.outbox) == 1
+
+
+@pytest.mark.django_db
+def test_notification_trigger_global(event, order, user, monkeypatch_on_commit):
+    djmail.outbox = []
+    user.notification_settings.create(
+        method='mail', event=None, action_type='pretix.event.order.paid', enabled=True
+    )
+    with transaction.atomic():
+        order.log_action('pretix.event.order.paid', {})
+    assert len(djmail.outbox) == 1
+
+
+@pytest.mark.django_db
+def test_notification_enabled_global_ignored_specific(event, order, user, monkeypatch_on_commit):
+    djmail.outbox = []
+    user.notification_settings.create(
+        method='mail', event=None, action_type='pretix.event.order.paid', enabled=True
+    )
+    user.notification_settings.create(
+        method='mail', event=event, action_type='pretix.event.order.paid', enabled=False
+    )
+    with transaction.atomic():
+        order.log_action('pretix.event.order.paid', {})
+    assert len(djmail.outbox) == 0
+
+
+@pytest.mark.django_db
+def test_notification_ignore_same_user(event, order, user, monkeypatch_on_commit):
+    djmail.outbox = []
+    user.notification_settings.create(
+        method='mail', event=event, action_type='pretix.event.order.paid', enabled=True
+    )
+    with transaction.atomic():
+        order.log_action('pretix.event.order.paid', {}, user=user)
+    assert len(djmail.outbox) == 0
+
+
+@pytest.mark.django_db
+def test_notification_ignore_insufficient_permissions(event, order, user, team, monkeypatch_on_commit):
+    djmail.outbox = []
+    team.can_view_orders = False
+    team.save()
+    user.notification_settings.create(
+        method='mail', event=event, action_type='pretix.event.order.paid', enabled=True
+    )
+    with transaction.atomic():
+        order.log_action('pretix.event.order.paid', {})
+    assert len(djmail.outbox) == 0
+
+# TODO: Test email content