Overdue order notification (#3114)

* Adds a background task to notify users when a PurchaseOrder becomes overdue

* Schedule the overdue purchaseorder check to occur daily

* Allow notifications to be sent to "Owner" instances

- Extract user information from the Owner instance

* add unit test to ensure notifications are sent for overdue purchase orders

* Adds notification for overdue sales orders

* Clean up notification display panel

- Simplify rendering
- Order "newest at top"
- Element alignment tweaks

* style fixes

* More style fixes

* Tweak notification padding

* Fix import order

* Adds task to notify user of overdue build orders

* Adds unit tests for build order notifications

* Refactor subject line for emails:

- Use the configured instance title as a prefix for the subject line

* Add email template for overdue build orders

* Fix unit tests to accommodate new default value

* Logic error fix

InvenTree/order/tests.py

@@ -3,12 +3,17 @@
 from datetime import datetime, timedelta
 
 import django.core.exceptions as django_exceptions
+from django.contrib.auth import get_user_model
+from django.contrib.auth.models import Group
 from django.test import TestCase
 
+import common.models
+import order.tasks
 from company.models import SupplierPart
 from InvenTree.status_codes import PurchaseOrderStatus
 from part.models import Part
 from stock.models import StockLocation
+from users.models import Owner
 
 from .models import PurchaseOrder, PurchaseOrderLineItem
 
@@ -24,7 +29,8 @@ class OrderTest(TestCase):
         'part',
         'location',
         'stock',
-        'order'
+        'order',
+        'users',
     ]
 
     def test_basics(self):
@@ -197,3 +203,37 @@ class OrderTest(TestCase):
             order.receive_line_item(line, loc, line.quantity, user=None)
 
         self.assertEqual(order.status, PurchaseOrderStatus.COMPLETE)
+
+    def test_overdue_notification(self):
+        """Test overdue purchase order notification
+
+        Ensure that a notification is sent when a PurchaseOrder becomes overdue
+        """
+        po = PurchaseOrder.objects.get(pk=1)
+
+        # Created by 'sam'
+        po.created_by = get_user_model().objects.get(pk=4)
+
+        # Responsible : 'Engineers' group
+        responsible = Owner.create(obj=Group.objects.get(pk=2))
+        po.responsible = responsible
+
+        # Target date = yesterday
+        po.target_date = datetime.now().date() - timedelta(days=1)
+        po.save()
+
+        # Check for overdue purchase orders
+        order.tasks.check_overdue_purchase_orders()
+
+        for user_id in [2, 3, 4]:
+            messages = common.models.NotificationMessage.objects.filter(
+                category='order.overdue_purchase_order',
+                user__id=user_id,
+            )
+
+            self.assertTrue(messages.exists())
+
+            msg = messages.first()
+
+            self.assertEqual(msg.target_object_id, 1)
+            self.assertEqual(msg.name, 'Overdue Purchase Order')