Merge branch 'master' of git://github.com/punteney/mongoengine

mongoengine/queryset.py

@@ -14,10 +14,14 @@ REPR_OUTPUT_SIZE = 20
 class InvalidQueryError(Exception):
     pass
 
-
 class OperationError(Exception):
     pass
 
+class MultipleObjectsReturned(Exception):
+    pass
+
+class DoesNotExist(Exception):
+    pass
 
 class Q(object):
     
@@ -292,6 +296,21 @@ class QuerySet(object):
 
         return mongo_query
 
+    def get(self, *q_objs, **query):
+        """Retrieve the the matching object raising 
+        'MultipleObjectsReturned' or 'DoesNotExist' exceptions
+        if multiple or no results are found.
+        """
+        self.__call__(*q_objs, **query)
+        count = self.count()
+        if count == 1:
+            return self[0]
+        elif count > 1:
+            raise MultipleObjectsReturned
+        else:
+            raise DoesNotExist
+
+
     def first(self):
         """Retrieve the first object matching the query.
         """

tests/queryset.py

@@ -2,7 +2,7 @@ import unittest
 import pymongo
 from datetime import datetime
 
-from mongoengine.queryset import QuerySet
+from mongoengine.queryset import QuerySet, MultipleObjectsReturned, DoesNotExist
 from mongoengine import *
 
 
@@ -135,6 +135,27 @@ class QuerySetTest(unittest.TestCase):
         person = self.Person.objects.with_id(person1.id)
         self.assertEqual(person.name, "User A")
 
+    def test_find_only_one(self):
+        """Ensure that a query using find_one returns a valid result.
+        """
+        # Try retrieving when no objects exists
+        self.assertRaises(DoesNotExist, self.Person.objects.get)
+
+        person1 = self.Person(name="User A", age=20)
+        person1.save()
+        person2 = self.Person(name="User B", age=30)
+        person2.save()
+
+        # Retrieve the first person from the database
+        self.assertRaises(MultipleObjectsReturned, self.Person.objects.get)
+
+        # Use a query to filter the people found to just person2
+        person = self.Person.objects.get(age=30)
+        self.assertEqual(person.name, "User B")
+
+        person = self.Person.objects.get(age__lt=30)
+        self.assertEqual(person.name, "User A")
+
     def test_filter_chaining(self):
         """Ensure filters can be chained together.
         """