Add some unit tests

- Saving a model automatically updates the reference_int field
- Data migrations are correctly applied

InvenTree/order/migrations/0052_auto_20211014_0631.py

@@ -9,12 +9,8 @@ def build_refs(apps, schema_editor):
     Rebuild the integer "reference fields" for existing Build objects
     """
 
-    print("\n - Rebuilding reference field for PurchaseOrder model...")
-
     PurchaseOrder = apps.get_model('order', 'purchaseorder')
 
-    n = PurchaseOrder.objects.count()
-
     for order in PurchaseOrder.objects.all():
 
         ref = 0
@@ -30,13 +26,8 @@ def build_refs(apps, schema_editor):
         order.reference_int = ref
         order.save()
 
-    print(f" - Updated {n} PurchaseOrder objects")
-    print("\n - Rebuilding reference field for SalesOrder model...")
-
     SalesOrder = apps.get_model('order', 'salesorder')
 
-    n = SalesOrder.objects.count()
-
     for order in SalesOrder.objects.all():
 
         ref = 0
@@ -52,9 +43,6 @@ def build_refs(apps, schema_editor):
         order.reference_int = ref
         order.save()
 
-    print(f" - Updated {n} SalesOrder objects")
-    print(f" - COMPLETE! -")
-
 
 def unbuild_refs(apps, schema_editor):
     """

InvenTree/order/test_migrations.py

@@ -0,0 +1,59 @@
+"""
+Unit tests for the 'order' model data migrations
+"""
+
+from django_test_migrations.contrib.unittest_case import MigratorTestCase
+
+from InvenTree import helpers
+
+
+class TestForwardMigrations(MigratorTestCase):
+    """
+    Test entire schema migration
+    """
+
+    migrate_from = ('order', helpers.getOldestMigrationFile('order'))
+    migrate_to = ('order', helpers.getNewestMigrationFile('order'))
+
+    def prepare(self):
+        """
+        Create initial data set
+        """
+
+        # Create a purchase order from a supplier
+        Company = self.old_state.apps.get_model('company', 'company')
+
+        supplier = Company.objects.create(
+            name='Supplier A',
+            description='A great supplier!',
+            is_supplier=True
+        )
+
+        PurchaseOrder = self.old_state.apps.get_model('order', 'purchaseorder')
+
+        # Create some orders
+        for ii in range(10):
+
+            order = PurchaseOrder.objects.create(
+                supplier=supplier,
+                reference=f"{ii}-abcde",
+                description="Just a test order"
+            )
+
+            # Initially, the 'reference_int' field is unavailable
+            with self.assertRaises(AttributeError):
+                print(order.reference_int)
+
+    def test_ref_field(self):
+        """
+        Test that the 'reference_int' field has been created and is filled out correctly
+        """
+
+        PurchaseOrder = self.new_state.apps.get_model('order', 'purchaseorder')
+
+        for ii in range(10):
+
+            order = PurchaseOrder.objects.get(reference=f"{ii}-abcde")
+
+            # The integer reference field must have been correctly updated
+        self.assertEqual(order.reference_int, ii)