PEP and unit testing fixes

InvenTree/build/fixtures/build.yaml

@@ -10,6 +10,10 @@
     status: 10  # PENDING
     creation_date: '2019-03-16'
     link: http://www.google.com
+    level: 0
+    lft: 0
+    rght: 0
+    tree_id: 0
 
 - model: build.build
   fields:
@@ -19,4 +23,8 @@
     status: 40  # COMPLETE
     quantity: 21
     notes: 'Some more simple notes'
-    creation_date: '2019-03-16'
+    creation_date: '2019-03-16'
+    level: 0
+    lft: 0
+    rght: 0
+    tree_id: 1

InvenTree/build/tests.py

@@ -39,7 +39,7 @@ class BuildTestSimple(TestCase):
         self.assertEqual(b.batch, 'B2')
         self.assertEqual(b.quantity, 21)
 
-        self.assertEqual(str(b), 'Build 21 x Orphan - A part without a category')
+        self.assertEqual(str(b), '21 x Orphan')
 
     def test_url(self):
         b1 = Build.objects.get(pk=1)

InvenTree/stock/models.py

@@ -433,7 +433,6 @@ class StockItem(MPTTModel):
 
         return max(self.quantity - self.allocation_count(), 0)
 
-
     def can_delete(self):
         """ Can this stock item be deleted? It can NOT be deleted under the following circumstances: