fix-#397: Allow specifying the '_cls' as a field for indexes

tests/document/class_methods.py

@@ -36,9 +36,9 @@ class ClassMethodsTest(unittest.TestCase):
     def test_definition(self):
         """Ensure that document may be defined using fields.
         """
-        self.assertEqual(['age', 'id', 'name'],
+        self.assertEqual(['_cls', 'age', 'id', 'name'],
                          sorted(self.Person._fields.keys()))
-        self.assertEqual(["IntField", "ObjectIdField", "StringField"],
+        self.assertEqual(["IntField", "ObjectIdField", "StringField", "StringField"],
                         sorted([x.__class__.__name__ for x in
                                 self.Person._fields.values()]))
 

tests/document/inheritance.py

@@ -163,7 +163,7 @@ class InheritanceTest(unittest.TestCase):
         class Employee(Person):
             salary = IntField()
 
-        self.assertEqual(['age', 'id', 'name', 'salary'],
+        self.assertEqual(['_cls', 'age', 'id', 'name', 'salary'],
                          sorted(Employee._fields.keys()))
         self.assertEqual(Employee._get_collection_name(),
                          Person._get_collection_name())
@@ -180,7 +180,7 @@ class InheritanceTest(unittest.TestCase):
         class Employee(Person):
             salary = IntField()
 
-        self.assertEqual(['age', 'id', 'name', 'salary'],
+        self.assertEqual(['_cls', 'age', 'id', 'name', 'salary'],
                          sorted(Employee._fields.keys()))
         self.assertEqual(Person(name="Bob", age=35).to_mongo().keys(),
                          ['_cls', 'name', 'age'])

tests/document/instance.py

@@ -462,7 +462,7 @@ class InstanceTest(unittest.TestCase):
         self.assertEqual(person['name'], 'Another User')
 
         # Length = length(assigned fields + id)
-        self.assertEqual(len(person), 3)
+        self.assertEqual(len(person), 4)
 
         self.assertTrue('age' in person)
         person.age = None

tests/fields/fields.py

@@ -3034,6 +3034,29 @@ class FieldTest(unittest.TestCase):
         test.dictionary  # Just access to test getter
         self.assertRaises(ValidationError, test.validate)
 
+    def test_cls_field(self):
+        class Animal(Document):
+            meta = {'allow_inheritance': True}
+
+        class Fish(Animal):
+            pass
+
+        class Mammal(Animal):
+            pass
+
+        class Dog(Mammal):
+            pass
+
+        class Human(Mammal):
+            pass
+
+        Animal.objects.delete()
+        Dog().save()
+        Fish().save()
+        Human().save()
+        self.assertEquals(Animal.objects(_cls__in=["Animal.Mammal.Dog", "Animal.Fish"]).count(), 2)
+        self.assertEquals(Animal.objects(_cls__in=["Animal.Fish.Guppy"]).count(), 0)
+
 
 if __name__ == '__main__':
     unittest.main()