Add initial migration unit test for the 'part' app

InvenTree/part/test_migrations.py

@@ -0,0 +1,52 @@
+"""
+Unit tests for the part model database migrations
+"""
+
+from django_test_migrations.contrib.unittest_case import MigratorTestCase
+
+from InvenTree import helpers
+
+
+class TestForwardMigrations(MigratorTestCase):
+    """
+    Test entire schema migration sequence for the part app
+    """
+
+    migrate_from = ('part', helpers.getOldestMigrationFile('part'))
+    migrate_to = ('part', helpers.getNewestMigrationFile('part'))
+
+    def prepare(self):
+        """
+        Create initial data
+        """
+
+        Part = self.old_state.apps.get_model('part', 'part')
+
+        Part.objects.create(name='A', description='My part A')
+        Part.objects.create(name='B', description='My part B')
+        Part.objects.create(name='C', description='My part C')
+        Part.objects.create(name='D', description='My part D')
+        Part.objects.create(name='E', description='My part E')
+
+        # Extract one part object to investigate
+        p = Part.objects.all().last()
+
+        # Initially some fields are not present
+        with self.assertRaises(AttributeError):
+            print(p.has_variants)
+        
+        with self.assertRaises(AttributeError):
+            print(p.is_template)
+
+
+    def test_models_exist(self):
+
+        Part = self.new_state.apps.get_model('part', 'part')
+
+        self.assertEqual(Part.objects.count(), 5)
+
+        for part in Part.objects.all():
+            part.is_template = True
+            part.save()
+            part.is_template = False
+            part.save()