Added support to fetch latest object from mongoengine queryset

Author: Arpit

mongoengine/queryset/base.py

@@ -298,6 +298,18 @@ def first(self):
             result = None
         return result
 
+    def last(self, *ordering_keys):
+        """Retrieve the latest object matching the query.
+
+        :param keys: fields to order the query results by; keys may be
+            prefixed with "+" or a "-" to determine the ordering direction.
+
+        """
+        if not ordering_keys:
+            ordering_keys = "-id"
+
+        return self.order_by(ordering_keys).first()
+
     def insert(
         self, doc_or_docs, load_bulk=True, write_concern=None, signal_kwargs=None
     ):

tests/queryset/test_queryset.py

@@ -2599,6 +2599,24 @@ def test_order_by(self):
         ages = [p.age for p in self.Person.objects.order_by("")]
         assert ages == [40, 20, 30]
 
+    def test_last(self):
+        """Ensure the retieval of the latest object from the QuerySet."""
+        person1 = self.Person(name="User B", age=40).save()
+        person2 = self.Person(name="User A", age=20).save()
+        person3 = self.Person(name="User C", age=30).save()
+
+        names = [p.name for p in self.Person.objects.last]
+        assert names == ["User B", "User C", "User A"]
+        assert self.Person.objects.last() == person3
+
+        person2.age = 31
+        person2.save()
+        assert self.Person.objects.last() == person3
+
+        person1.age = 41
+        person1.save()
+        assert self.Person.objects.last() == person3
+
     def test_order_by_optional(self):
         class BlogPost(Document):
             title = StringField()