Adds basic test for collector

Author: kingbuzzman

factory/django.py

@@ -226,7 +226,7 @@ def _refresh_database_pks(cls, model_cls, objs):
     @classmethod
     def _bulk_create(cls, size, **kwargs):
         models_to_create = cls.build_batch(size, **kwargs)
-        collector = Collector()
+        collector = DependencyInsertOrderCollector()
         collector.collect(cls, models_to_create)
         collector.sort()
         for model_cls, objs in collector.data.items():
@@ -339,7 +339,7 @@ def _make_data(self, params):
         return thumb_io.getvalue()
 
 
-class Collector:
+class DependencyInsertOrderCollector:
     def __init__(self):
         # Initially, {model: {instances}}, later values become lists.
         self.data = defaultdict(list)

tests/test_django.py

@@ -175,6 +175,16 @@ class Meta:
     level_2 = factory.SubFactory(Level2Factory)
 
 
+class DependencyInsertOrderCollector(django_test.TestCase):
+
+    def test_empty(self):
+        collector = factory.django.DependencyInsertOrderCollector()
+        collector.collect(Level2Factory, [])
+        collector.sort()
+
+        self.assertEqual(collector.data, {})
+
+
 @unittest.skipIf(SKIP_BULK_INSERT, "bulk insert not supported by current db.")
 class DjangoBulkInsert(django_test.TestCase):