Improve the health of this package (#1428)

tests/queryset/transform.py

@@ -238,7 +238,8 @@ class TransformTest(unittest.TestCase):
         box = [(35.0, -125.0), (40.0, -100.0)]
         # I *meant* to execute location__within_box=box
         events = Event.objects(location__within=box)
-        self.assertRaises(InvalidQueryError, lambda: events.count())
+        with self.assertRaises(InvalidQueryError):
+            events.count()
 
 
 if __name__ == '__main__':