added testcase for save create with shard key

tests/document/test_instance.py

@@ -501,7 +501,7 @@ class TestDocumentInstance(MongoDBTestCase):
         doc.reload()
         Animal.drop_collection()
 
-    def test_update_shard_key_routing(self):
+    def test_save_update_shard_key_routing(self):
         """Ensures updating a doc with a specified shard_key includes it in
         the query.
         """
@@ -529,6 +529,36 @@ class TestDocumentInstance(MongoDBTestCase):
 
         Animal.drop_collection()
 
+    def test_save_create_shard_key_routing(self):
+        """Ensures inserting a doc with a specified shard_key includes it in
+        the query.
+        """
+
+        class Animal(Document):
+            _id = UUIDField(binary=False, primary_key=True, default=uuid.uuid4)
+            is_mammal = BooleanField()
+            name = StringField()
+            meta = {"shard_key": ("is_mammal",)}
+
+        Animal.drop_collection()
+        doc = Animal(is_mammal=True, name="Dog")
+
+        mongo_db = get_mongodb_version()
+
+        with query_counter() as q:
+            doc.save()
+            query_op = q.db.system.profile.find({"ns": "mongoenginetest.animal"})[0]
+            assert query_op["op"] == "command"
+            assert query_op["command"]["findAndModify"] == "animal"
+            if mongo_db <= MONGODB_34:
+                assert set(query_op["query"].keys()) == set(["_id", "is_mammal"])
+            else:
+                assert set(query_op["command"]["query"].keys()) == set(
+                    ["_id", "is_mammal"]
+                )
+
+        Animal.drop_collection()
+
     def test_reload_with_changed_fields(self):
         """Ensures reloading will not affect changed fields"""