Delete part via API (#3135)

* Updates for the PartRelated model

- Deleting a part also deletes the relationships
- Add unique_together requirement
- Bug fixes
- Added unit tests

* Adds JS function to delete a part instance

* Remove legacy delete view

* JS linting

InvenTree/part/test_part.py

@@ -15,8 +15,8 @@ from common.notifications import UIMessageNotification, storage
 from InvenTree import version
 from InvenTree.helpers import InvenTreeTestCase
 
-from .models import (Part, PartCategory, PartCategoryStar, PartStar,
-                     PartTestTemplate, rename_part_image)
+from .models import (Part, PartCategory, PartCategoryStar, PartRelated,
+                     PartStar, PartTestTemplate, rename_part_image)
 from .templatetags import inventree_extras
 
 
@@ -280,6 +280,53 @@ class PartTest(TestCase):
 
         self.assertEqual(len(p.metadata.keys()), 4)
 
+    def test_related(self):
+        """Unit tests for the PartRelated model"""
+
+        # Create a part relationship
+        PartRelated.objects.create(part_1=self.r1, part_2=self.r2)
+        self.assertEqual(PartRelated.objects.count(), 1)
+
+        # Creating a duplicate part relationship should fail
+        with self.assertRaises(ValidationError):
+            PartRelated.objects.create(part_1=self.r1, part_2=self.r2)
+
+        # Creating an 'inverse' duplicate relationship should also fail
+        with self.assertRaises(ValidationError):
+            PartRelated.objects.create(part_1=self.r2, part_2=self.r1)
+
+        # Try to add a self-referential relationship
+        with self.assertRaises(ValidationError):
+            PartRelated.objects.create(part_1=self.r2, part_2=self.r2)
+
+        # Test relation lookup for each part
+        r1_relations = self.r1.get_related_parts()
+        self.assertEqual(len(r1_relations), 1)
+        self.assertIn(self.r2, r1_relations)
+
+        r2_relations = self.r2.get_related_parts()
+        self.assertEqual(len(r2_relations), 1)
+        self.assertIn(self.r1, r2_relations)
+
+        # Delete a part, ensure the relationship also gets deleted
+        self.r1.delete()
+
+        self.assertEqual(PartRelated.objects.count(), 0)
+        self.assertEqual(len(self.r2.get_related_parts()), 0)
+
+        # Add multiple part relationships to self.r2
+        for p in Part.objects.all().exclude(pk=self.r2.pk):
+            PartRelated.objects.create(part_1=p, part_2=self.r2)
+
+        n = Part.objects.count() - 1
+
+        self.assertEqual(PartRelated.objects.count(), n)
+        self.assertEqual(len(self.r2.get_related_parts()), n)
+
+        # Deleting r2 should remove *all* relationships
+        self.r2.delete()
+        self.assertEqual(PartRelated.objects.count(), 0)
+
 
 class TestTemplateTest(TestCase):
     """Unit test for the TestTemplate class"""