QuerySet.modify() method to provide find_and_modify() like behaviour

tests/queryset/modify.py

@@ -0,0 +1,102 @@
+import sys
+sys.path[0:0] = [""]
+
+import unittest
+
+from mongoengine import connect, Document, IntField
+
+__all__ = ("FindAndModifyTest",)
+
+
+class Doc(Document):
+    id = IntField(primary_key=True)
+    value = IntField()
+
+
+class FindAndModifyTest(unittest.TestCase):
+
+    def setUp(self):
+        connect(db="mongoenginetest")
+        Doc.drop_collection()
+
+    def assertDbEqual(self, docs):
+        self.assertEqual(list(Doc._collection.find().sort("id")), docs)
+
+    def test_modify(self):
+        Doc(id=0, value=0).save()
+        doc = Doc(id=1, value=1).save()
+
+        old_doc = Doc.objects(id=1).modify(set__value=-1)
+        self.assertEqual(old_doc.to_json(), doc.to_json())
+        self.assertDbEqual([{"_id": 0, "value": 0}, {"_id": 1, "value": -1}])
+
+    def test_modify_with_new(self):
+        Doc(id=0, value=0).save()
+        doc = Doc(id=1, value=1).save()
+
+        new_doc = Doc.objects(id=1).modify(set__value=-1, new=True)
+        doc.value = -1
+        self.assertEqual(new_doc.to_json(), doc.to_json())
+        self.assertDbEqual([{"_id": 0, "value": 0}, {"_id": 1, "value": -1}])
+
+    def test_modify_not_existing(self):
+        Doc(id=0, value=0).save()
+        self.assertEqual(Doc.objects(id=1).modify(set__value=-1), None)
+        self.assertDbEqual([{"_id": 0, "value": 0}])
+
+    def test_modify_with_upsert(self):
+        Doc(id=0, value=0).save()
+        old_doc = Doc.objects(id=1).modify(set__value=1, upsert=True)
+        self.assertEqual(old_doc, None)
+        self.assertDbEqual([{"_id": 0, "value": 0}, {"_id": 1, "value": 1}])
+
+    def test_modify_with_upsert_existing(self):
+        Doc(id=0, value=0).save()
+        doc = Doc(id=1, value=1).save()
+
+        old_doc = Doc.objects(id=1).modify(set__value=-1, upsert=True)
+        self.assertEqual(old_doc.to_json(), doc.to_json())
+        self.assertDbEqual([{"_id": 0, "value": 0}, {"_id": 1, "value": -1}])
+
+    def test_modify_with_upsert_with_new(self):
+        Doc(id=0, value=0).save()
+        new_doc = Doc.objects(id=1).modify(upsert=True, new=True, set__value=1)
+        self.assertEqual(new_doc.to_mongo(), {"_id": 1, "value": 1})
+        self.assertDbEqual([{"_id": 0, "value": 0}, {"_id": 1, "value": 1}])
+
+    def test_modify_with_remove(self):
+        Doc(id=0, value=0).save()
+        doc = Doc(id=1, value=1).save()
+
+        old_doc = Doc.objects(id=1).modify(remove=True)
+        self.assertEqual(old_doc.to_json(), doc.to_json())
+        self.assertDbEqual([{"_id": 0, "value": 0}])
+
+    def test_find_and_modify_with_remove_not_existing(self):
+        Doc(id=0, value=0).save()
+        self.assertEqual(Doc.objects(id=1).modify(remove=True), None)
+        self.assertDbEqual([{"_id": 0, "value": 0}])
+
+    def test_modify_with_order_by(self):
+        Doc(id=0, value=3).save()
+        Doc(id=1, value=2).save()
+        Doc(id=2, value=1).save()
+        doc = Doc(id=3, value=0).save()
+
+        old_doc = Doc.objects().order_by("-id").modify(set__value=-1)
+        self.assertEqual(old_doc.to_json(), doc.to_json())
+        self.assertDbEqual([
+            {"_id": 0, "value": 3}, {"_id": 1, "value": 2},
+            {"_id": 2, "value": 1}, {"_id": 3, "value": -1}])
+
+    def test_modify_with_fields(self):
+        Doc(id=0, value=0).save()
+        Doc(id=1, value=1).save()
+
+        old_doc = Doc.objects(id=1).only("id").modify(set__value=-1)
+        self.assertEqual(old_doc.to_mongo(), {"_id": 1})
+        self.assertDbEqual([{"_id": 0, "value": 0}, {"_id": 1, "value": -1}])
+
+
+if __name__ == '__main__':
+    unittest.main()