test_instance.py

import os
import pickle
import unittest
import uuid
import weakref
from datetime import datetime
from unittest.mock import Mock

import bson
import pytest
from bson import DBRef, ObjectId
from pymongo.errors import DuplicateKeyError

from mongoengine import *
from mongoengine import signals
from mongoengine.base import (
    _document_registry,
    _undefined_document_delete_rules,
    get_document,
)
from mongoengine.connection import get_db
from mongoengine.context_managers import query_counter, switch_db
from mongoengine.errors import (
    FieldDoesNotExist,
    InvalidDocumentError,
    InvalidQueryError,
    NotRegistered,
    NotUniqueError,
    SaveConditionError,
)
from mongoengine.mongodb_support import (
    MONGODB_34,
    MONGODB_36,
    get_mongodb_version,
)
from mongoengine.pymongo_support import (
    PYMONGO_VERSION,
    list_collection_names,
)
from mongoengine.queryset import NULLIFY, Q
from tests import fixtures
from tests.fixtures import (
    PickleDynamicEmbedded,
    PickleDynamicTest,
    PickleEmbedded,
    PickleSignalsTest,
    PickleTest,
)
from tests.utils import MongoDBTestCase, get_as_pymongo

TEST_IMAGE_PATH = os.path.join(os.path.dirname(__file__), "../fields/mongoengine.png")


class TestDocumentInstance(MongoDBTestCase):
    def setUp(self):
        class Job(EmbeddedDocument):
            name = StringField()
            years = IntField()

        class Person(Document):
            name = StringField()
            age = IntField()
            job = EmbeddedDocumentField(Job)

            non_field = True

            meta = {"allow_inheritance": True}

        self.Person = Person
        self.Job = Job

    def tearDown(self):
        for collection in list_collection_names(self.db):
            self.db.drop_collection(collection)

    def _assert_db_equal(self, docs):
        assert list(self.Person._get_collection().find().sort("id")) == sorted(
            docs, key=lambda doc: doc["_id"]
        )

    def _assert_has_instance(self, field, instance):
        assert hasattr(field, "_instance")
        assert field._instance is not None
        if isinstance(field._instance, weakref.ProxyType):
            assert field._instance.__eq__(instance)
        else:
            assert field._instance == instance

    def test_capped_collection(self):
        """Ensure that capped collections work properly."""

        class Log(Document):
            date = DateTimeField(default=datetime.now)
            meta = {"max_documents": 10, "max_size": 4096}

        Log.drop_collection()

        # Ensure that the collection handles up to its maximum
        for _ in range(10):
            Log().save()

        assert Log.objects.count() == 10

        # Check that extra documents don't increase the size
        Log().save()
        assert Log.objects.count() == 10

        options = Log.objects._collection.options()
        assert options["capped"] is True
        assert options["max"] == 10
        assert options["size"] == 4096

        # Check that the document cannot be redefined with different options
        class Log(Document):
            date = DateTimeField(default=datetime.now)
            meta = {"max_documents": 11}

        # Accessing Document.objects creates the collection
        with pytest.raises(InvalidCollectionError):
            Log.objects

    def test_capped_collection_default(self):
        """Ensure that capped collections defaults work properly."""

        class Log(Document):
            date = DateTimeField(default=datetime.now)
            meta = {"max_documents": 10}

        Log.drop_collection()

        # Create a doc to create the collection
        Log().save()

        options = Log.objects._collection.options()
        assert options["capped"] is True
        assert options["max"] == 10
        assert options["size"] == 10 * 2**20

        # Check that the document with default value can be recreated
        class Log(Document):
            date = DateTimeField(default=datetime.now)
            meta = {"max_documents": 10}

        # Create the collection by accessing Document.objects
        Log.objects

    def test_capped_collection_no_max_size_problems(self):
        """Ensure that capped collections with odd max_size work properly.
        MongoDB rounds up max_size to next multiple of 256, recreating a doc
        with the same spec failed in mongoengine <0.10
        """

        class Log(Document):
            date = DateTimeField(default=datetime.now)
            meta = {"max_size": 10000}

        Log.drop_collection()

        # Create a doc to create the collection
        Log().save()

        options = Log.objects._collection.options()
        assert options["capped"] is True
        assert options["size"] >= 10000

        # Check that the document with odd max_size value can be recreated
        class Log(Document):
            date = DateTimeField(default=datetime.now)
            meta = {"max_size": 10000}

        # Create the collection by accessing Document.objects
        Log.objects

    def test_repr(self):
        """Ensure that unicode representation works"""

        class Article(Document):
            title = StringField()

            def __unicode__(self):
                return self.title

        doc = Article(title="привет мир")

        assert "<Article: привет мир>" == repr(doc)

    def test_repr_none(self):
        """Ensure None values are handled correctly."""

        class Article(Document):
            title = StringField()

            def __str__(self):
                return None

        doc = Article(title="привет мир")
        assert "<Article: None>" == repr(doc)

    def test_queryset_resurrects_dropped_collection(self):
        self.Person.drop_collection()
        assert list(self.Person.objects()) == []

        # Ensure works correctly with inhertited classes
        class Actor(self.Person):
            pass

        Actor.objects()
        self.Person.drop_collection()
        assert list(Actor.objects()) == []

    def test_polymorphic_references(self):
        """Ensure that the correct subclasses are returned from a query
        when using references / generic references
        """

        class Animal(Document):
            meta = {"allow_inheritance": True}

        class Fish(Animal):
            pass

        class Mammal(Animal):
            pass

        class Dog(Mammal):
            pass

        class Human(Mammal):
            pass

        class Zoo(Document):
            animals = ListField(ReferenceField(Animal))

        Zoo.drop_collection()
        Animal.drop_collection()

        Animal().save()
        Fish().save()
        Mammal().save()
        Dog().save()
        Human().save()

        # Save a reference to each animal
        zoo = Zoo(animals=Animal.objects)
        zoo.save()
        zoo.reload()

        classes = [a.__class__ for a in Zoo.objects.first().animals]
        assert classes == [Animal, Fish, Mammal, Dog, Human]

        Zoo.drop_collection()

        class Zoo(Document):
            animals = ListField(GenericReferenceField())

        # Save a reference to each animal
        zoo = Zoo(animals=Animal.objects)
        zoo.save()
        zoo.reload()

        classes = [a.__class__ for a in Zoo.objects.first().animals]
        assert classes == [Animal, Fish, Mammal, Dog, Human]

    def test_reference_inheritance(self):
        class Stats(Document):
            created = DateTimeField(default=datetime.now)

            meta = {"allow_inheritance": False}

        class CompareStats(Document):
            generated = DateTimeField(default=datetime.now)
            stats = ListField(ReferenceField(Stats))

        Stats.drop_collection()
        CompareStats.drop_collection()

        list_stats = []

        for i in range(10):
            s = Stats()
            s.save()
            list_stats.append(s)

        cmp_stats = CompareStats(stats=list_stats)
        cmp_stats.save()

        assert list_stats == CompareStats.objects.first().stats

    def test_db_field_load(self):
        """Ensure we load data correctly from the right db field."""

        class Person(Document):
            name = StringField(required=True)
            _rank = StringField(required=False, db_field="rank")

            @property
            def rank(self):
                return self._rank or "Private"

        Person.drop_collection()

        Person(name="Jack", _rank="Corporal").save()

        Person(name="Fred").save()

        assert Person.objects.get(name="Jack").rank == "Corporal"
        assert Person.objects.get(name="Fred").rank == "Private"

    def test_db_embedded_doc_field_load(self):
        """Ensure we load embedded document data correctly."""

        class Rank(EmbeddedDocument):
            title = StringField(required=True)

        class Person(Document):
            name = StringField(required=True)
            rank_ = EmbeddedDocumentField(Rank, required=False, db_field="rank")

            @property
            def rank(self):
                if self.rank_ is None:
                    return "Private"
                return self.rank_.title

        Person.drop_collection()

        Person(name="Jack", rank_=Rank(title="Corporal")).save()
        Person(name="Fred").save()

        assert Person.objects.get(name="Jack").rank == "Corporal"
        assert Person.objects.get(name="Fred").rank == "Private"

    def test_custom_id_field(self):
        """Ensure that documents may be created with custom primary keys."""

        class User(Document):
            username = StringField(primary_key=True)
            name = StringField()

            meta = {"allow_inheritance": True}

        User.drop_collection()

        assert User._fields["username"].db_field == "_id"
        assert User._meta["id_field"] == "username"

        User.objects.create(username="test", name="test user")
        user = User.objects.first()
        assert user.id == "test"
        assert user.pk == "test"
        user_dict = User.objects._collection.find_one()
        assert user_dict["_id"] == "test"

    def test_change_custom_id_field_in_subclass(self):
        """Subclasses cannot override which field is the primary key."""

        class User(Document):
            username = StringField(primary_key=True)
            name = StringField()
            meta = {"allow_inheritance": True}

        with pytest.raises(ValueError, match="Cannot override primary key field"):

            class EmailUser(User):
                email = StringField(primary_key=True)

    def test_custom_id_field_is_required(self):
        """Ensure the custom primary key field is required."""

        class User(Document):
            username = StringField(primary_key=True)
            name = StringField()

        with pytest.raises(ValidationError) as exc_info:
            User(name="test").save()
        assert "Field is required: ['username']" in str(exc_info.value)

    def test_document_not_registered(self):
        class Place(Document):
            name = StringField()

            meta = {"allow_inheritance": True}

        class NicePlace(Place):
            pass

        Place.drop_collection()

        Place(name="London").save()
        NicePlace(name="Buckingham Palace").save()

        # Mimic Place and NicePlace definitions being in a different file
        # and the NicePlace model not being imported in at query time.
        del _document_registry["Place.NicePlace"]

        with pytest.raises(NotRegistered):
            list(Place.objects.all())

    def test_document_registry_regressions(self):
        class Location(Document):
            name = StringField()
            meta = {"allow_inheritance": True}

        class Area(Location):
            location = ReferenceField("Location", dbref=True)

        Location.drop_collection()

        assert Area == get_document("Area")
        assert Area == get_document("Location.Area")

    def test_creation(self):
        """Ensure that document may be created using keyword arguments."""
        person = self.Person(name="Test User", age=30)
        assert person.name == "Test User"
        assert person.age == 30

    def test__qs_property_does_not_raise(self):
        # ensures no regression of #2500
        class MyDocument(Document):
            pass

        MyDocument.drop_collection()
        object = MyDocument()
        object._qs().insert([MyDocument()])
        assert MyDocument.objects.count() == 1

    def test_to_dbref(self):
        """Ensure that you can get a dbref of a document."""
        person = self.Person(name="Test User", age=30)
        with pytest.raises(OperationError):
            person.to_dbref()
        person.save()
        person.to_dbref()

    def test_key_like_attribute_access(self):
        person = self.Person(age=30)
        assert person["age"] == 30
        with pytest.raises(KeyError):
            person["unknown_attr"]

    def test_save_abstract_document(self):
        """Saving an abstract document should fail."""

        class Doc(Document):
            name = StringField()
            meta = {"abstract": True}

        with pytest.raises(InvalidDocumentError):
            Doc(name="aaa").save()

    def test_reload(self):
        """Ensure that attributes may be reloaded."""
        person = self.Person(name="Test User", age=20)
        person.save()

        person_obj = self.Person.objects.first()
        person_obj.name = "Mr Test User"
        person_obj.age = 21
        person_obj.save()

        assert person.name == "Test User"
        assert person.age == 20

        person.reload("age")
        assert person.name == "Test User"
        assert person.age == 21

        person.reload()
        assert person.name == "Mr Test User"
        assert person.age == 21

        person.reload()
        assert person.name == "Mr Test User"
        assert person.age == 21

    def test_reload_sharded(self):
        class Animal(Document):
            superphylum = StringField()
            meta = {"shard_key": ("superphylum",)}

        Animal.drop_collection()
        doc = Animal.objects.create(superphylum="Deuterostomia")

        mongo_db = get_mongodb_version()
        CMD_QUERY_KEY = "command" if mongo_db >= MONGODB_36 else "query"
        with query_counter() as q:
            doc.reload()
            query_op = q.db.system.profile.find({"ns": "mongoenginetest.animal"})[0]
            assert set(query_op[CMD_QUERY_KEY]["filter"].keys()) == {
                "_id",
                "superphylum",
            }

    def test_reload_sharded_with_db_field(self):
        class Person(Document):
            nationality = StringField(db_field="country")
            meta = {"shard_key": ("nationality",)}

        Person.drop_collection()
        doc = Person.objects.create(nationality="Poland")

        mongo_db = get_mongodb_version()
        CMD_QUERY_KEY = "command" if mongo_db >= MONGODB_36 else "query"
        with query_counter() as q:
            doc.reload()
            query_op = q.db.system.profile.find({"ns": "mongoenginetest.person"})[0]
            assert set(query_op[CMD_QUERY_KEY]["filter"].keys()) == {"_id", "country"}

    def test_reload_sharded_nested(self):
        class SuperPhylum(EmbeddedDocument):
            name = StringField()

        class Animal(Document):
            superphylum = EmbeddedDocumentField(SuperPhylum)
            meta = {"shard_key": ("superphylum.name",)}

        Animal.drop_collection()
        doc = Animal(superphylum=SuperPhylum(name="Deuterostomia"))
        doc.save()
        doc.reload()
        Animal.drop_collection()

    def test_save_update_shard_key_routing(self):
        """Ensures updating a doc with a specified shard_key includes it in
        the query.
        """

        class Animal(Document):
            is_mammal = BooleanField()
            name = StringField()
            meta = {"shard_key": ("is_mammal", "id")}

        Animal.drop_collection()
        doc = Animal(is_mammal=True, name="Dog")
        doc.save()

        mongo_db = get_mongodb_version()

        with query_counter() as q:
            doc.name = "Cat"
            doc.save()
            query_op = q.db.system.profile.find({"ns": "mongoenginetest.animal"})[0]
            assert query_op["op"] == "update"
            if mongo_db <= MONGODB_34:
                assert set(query_op["query"].keys()) == {"_id", "is_mammal"}
            else:
                assert set(query_op["command"]["q"].keys()) == {"_id", "is_mammal"}

        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")

        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"
            assert set(query_op["command"]["query"].keys()) == {"_id", "is_mammal"}

        Animal.drop_collection()

    def test_reload_with_changed_fields(self):
        """Ensures reloading will not affect changed fields"""

        class User(Document):
            name = StringField()
            number = IntField()

        User.drop_collection()

        user = User(name="Bob", number=1).save()
        user.name = "John"
        user.number = 2

        assert user._get_changed_fields() == ["name", "number"]
        user.reload("number")
        assert user._get_changed_fields() == ["name"]
        user.save()
        user.reload()
        assert user.name == "John"

    def test_reload_referencing(self):
        """Ensures reloading updates weakrefs correctly."""

        class Embedded(EmbeddedDocument):
            dict_field = DictField()
            list_field = ListField()

        class Doc(Document):
            dict_field = DictField()
            list_field = ListField()
            embedded_field = EmbeddedDocumentField(Embedded)

        Doc.drop_collection()
        doc = Doc()
        doc.dict_field = {"hello": "world"}
        doc.list_field = ["1", 2, {"hello": "world"}]

        embedded_1 = Embedded()
        embedded_1.dict_field = {"hello": "world"}
        embedded_1.list_field = ["1", 2, {"hello": "world"}]
        doc.embedded_field = embedded_1
        doc.save()

        doc = doc.reload(10)
        doc.list_field.append(1)
        doc.dict_field["woot"] = "woot"
        doc.embedded_field.list_field.append(1)
        doc.embedded_field.dict_field["woot"] = "woot"

        changed = doc._get_changed_fields()
        assert changed == [
            "list_field",
            "dict_field.woot",
            "embedded_field.list_field",
            "embedded_field.dict_field.woot",
        ]
        doc.save()

        assert len(doc.list_field) == 4
        doc = doc.reload(10)
        assert doc._get_changed_fields() == []
        assert len(doc.list_field) == 4
        assert len(doc.dict_field) == 2
        assert len(doc.embedded_field.list_field) == 4
        assert len(doc.embedded_field.dict_field) == 2

        doc.list_field.append(1)
        doc.save()
        doc.dict_field["extra"] = 1
        doc = doc.reload(10, "list_field")
        assert doc._get_changed_fields() == ["dict_field.extra"]
        assert len(doc.list_field) == 5
        assert len(doc.dict_field) == 3
        assert len(doc.embedded_field.list_field) == 4
        assert len(doc.embedded_field.dict_field) == 2

    def test_reload_doesnt_exist(self):
        class Foo(Document):
            pass

        f = Foo()
        with pytest.raises(Foo.DoesNotExist):
            f.reload()

        f.save()
        f.delete()

        with pytest.raises(Foo.DoesNotExist):
            f.reload()

    def test_reload_of_non_strict_with_special_field_name(self):
        """Ensures reloading works for documents with meta strict is False."""

        class Post(Document):
            meta = {"strict": False}
            title = StringField()
            items = ListField()

        Post.drop_collection()

        Post._get_collection().insert_one(
            {"title": "Items eclipse", "items": ["more lorem", "even more ipsum"]}
        )

        post = Post.objects.first()
        post.reload()
        assert post.title == "Items eclipse"
        assert post.items == ["more lorem", "even more ipsum"]

    def test_dictionary_access(self):
        """Ensure that dictionary-style field access works properly."""
        person = self.Person(name="Test User", age=30, job=self.Job())
        assert person["name"] == "Test User"

        with pytest.raises(KeyError):
            person.__getitem__("salary")
        with pytest.raises(KeyError):
            person.__setitem__("salary", 50)

        person["name"] = "Another User"
        assert person["name"] == "Another User"

        # Length = length(assigned fields + id)
        assert len(person) == 5

        assert "age" in person
        person.age = None
        assert "age" not in person
        assert "nationality" not in person

    def test_embedded_document_to_mongo(self):
        class Person(EmbeddedDocument):
            name = StringField()
            age = IntField()

            meta = {"allow_inheritance": True}

        class Employee(Person):
            salary = IntField()

        assert sorted(Person(name="Bob", age=35).to_mongo().keys()) == [
            "_cls",
            "age",
            "name",
        ]
        assert sorted(Employee(name="Bob", age=35, salary=0).to_mongo().keys()) == [
            "_cls",
            "age",
            "name",
            "salary",
        ]

    def test_embedded_document_to_mongo_id(self):
        class SubDoc(EmbeddedDocument):
            id = StringField(required=True)

        sub_doc = SubDoc(id="abc")
        assert list(sub_doc.to_mongo().keys()) == ["id"]

    def test_embedded_document(self):
        """Ensure that embedded documents are set up correctly."""

        class Comment(EmbeddedDocument):
            content = StringField()

        assert "content" in Comment._fields
        assert "id" not in Comment._fields

    def test_embedded_document_instance(self):
        """Ensure that embedded documents can reference parent instance."""

        class Embedded(EmbeddedDocument):
            string = StringField()

        class Doc(Document):
            embedded_field = EmbeddedDocumentField(Embedded)

        Doc.drop_collection()

        doc = Doc(embedded_field=Embedded(string="Hi"))
        self._assert_has_instance(doc.embedded_field, doc)

        doc.save()
        doc = Doc.objects.get()
        self._assert_has_instance(doc.embedded_field, doc)

    def test_embedded_document_complex_instance(self):
        """Ensure that embedded documents in complex fields can reference
        parent instance.
        """

        class Embedded(EmbeddedDocument):
            string = StringField()

        class Doc(Document):
            embedded_field = ListField(EmbeddedDocumentField(Embedded))

        Doc.drop_collection()
        doc = Doc(embedded_field=[Embedded(string="Hi")])
        self._assert_has_instance(doc.embedded_field[0], doc)

        doc.save()
        doc = Doc.objects.get()
        self._assert_has_instance(doc.embedded_field[0], doc)

    def test_embedded_document_complex_instance_no_use_db_field(self):
        """Ensure that use_db_field is propagated to list of Emb Docs."""

        class Embedded(EmbeddedDocument):
            string = StringField(db_field="s")

        class Doc(Document):
            embedded_field = ListField(EmbeddedDocumentField(Embedded))

        d = (
            Doc(embedded_field=[Embedded(string="Hi")])
            .to_mongo(use_db_field=False)
            .to_dict()
        )
        assert d["embedded_field"] == [{"string": "Hi"}]

    def test_instance_is_set_on_setattr(self):
        class Email(EmbeddedDocument):
            email = EmailField()

        class Account(Document):
            email = EmbeddedDocumentField(Email)

        Account.drop_collection()

        acc = Account()
        acc.email = Email(email="test@example.com")
        self._assert_has_instance(acc._data["email"], acc)
        acc.save()

        acc1 = Account.objects.first()
        self._assert_has_instance(acc1._data["email"], acc1)

    def test_instance_is_set_on_setattr_on_embedded_document_list(self):
        class Email(EmbeddedDocument):
            email = EmailField()

        class Account(Document):
            emails = EmbeddedDocumentListField(Email)

        Account.drop_collection()
        acc = Account()
        acc.emails = [Email(email="test@example.com")]
        self._assert_has_instance(acc._data["emails"][0], acc)
        acc.save()

        acc1 = Account.objects.first()
        self._assert_has_instance(acc1._data["emails"][0], acc1)

    def test_save_checks_that_clean_is_called(self):
        class CustomError(Exception):
            pass

        class TestDocument(Document):
            def clean(self):
                raise CustomError()

        with pytest.raises(CustomError):
            TestDocument().save()

        TestDocument().save(clean=False)

    def test_save_signal_pre_save_post_validation_makes_change_to_doc(self):
        class BlogPost(Document):
            content = StringField()

            @classmethod
            def pre_save_post_validation(cls, sender, document, **kwargs):
                document.content = "checked"

        signals.pre_save_post_validation.connect(
            BlogPost.pre_save_post_validation, sender=BlogPost
        )

        BlogPost.drop_collection()

        post = BlogPost(content="unchecked").save()
        assert post.content == "checked"
        # Make sure pre_save_post_validation changes makes it to the db
        raw_doc = get_as_pymongo(post)
        assert raw_doc == {"content": "checked", "_id": post.id}

        # Important to disconnect as it could cause some assertions in test_signals
        # to fail (due to the garbage collection timing of this signal)
        signals.pre_save_post_validation.disconnect(BlogPost.pre_save_post_validation)

    def test_document_clean(self):
        class TestDocument(Document):
            status = StringField()
            cleaned = BooleanField(default=False)

            def clean(self):
                self.cleaned = True

        TestDocument.drop_collection()

        t = TestDocument(status="draft")

        # Ensure clean=False prevent call to clean
        t = TestDocument(status="published")
        t.save(clean=False)
        assert t.status == "published"
        assert t.cleaned is False

        t = TestDocument(status="published")
        assert t.cleaned is False
        t.save(clean=True)
        assert t.status == "published"
        assert t.cleaned is True
        raw_doc = get_as_pymongo(t)
        # Make sure clean changes makes it to the db
        assert raw_doc == {"status": "published", "cleaned": True, "_id": t.id}

    def test_document_embedded_clean(self):
        class TestEmbeddedDocument(EmbeddedDocument):
            x = IntField(required=True)
            y = IntField(required=True)
            z = IntField(required=True)

            meta = {"allow_inheritance": False}

            def clean(self):
                if self.z:
                    if self.z != self.x + self.y:
                        raise ValidationError("Value of z != x + y")
                else:
                    self.z = self.x + self.y

        class TestDocument(Document):
            doc = EmbeddedDocumentField(TestEmbeddedDocument)
            status = StringField()

        TestDocument.drop_collection()

        t = TestDocument(doc=TestEmbeddedDocument(x=10, y=25, z=15))

        with pytest.raises(ValidationError) as exc_info:
            t.save()

        expected_msg = "Value of z != x + y"
        assert expected_msg in str(exc_info.value)
        assert exc_info.value.to_dict() == {"doc": {"__all__": expected_msg}}

        t = TestDocument(doc=TestEmbeddedDocument(x=10, y=25)).save()
        assert t.doc.z == 35

        # Asserts not raises
        t = TestDocument(doc=TestEmbeddedDocument(x=15, y=35, z=5))
        t.save(clean=False)

    def test_modify_empty(self):
        doc = self.Person(name="bob", age=10).save()

        with pytest.raises(InvalidDocumentError):
            self.Person().modify(set__age=10)

        self._assert_db_equal([dict(doc.to_mongo())])

    def test_modify_invalid_query(self):
        doc1 = self.Person(name="bob", age=10).save()
        doc2 = self.Person(name="jim", age=20).save()
        docs = [dict(doc1.to_mongo()), dict(doc2.to_mongo())]

        with pytest.raises(InvalidQueryError):
            doc1.modify({"id": doc2.id}, set__value=20)

        self._assert_db_equal(docs)

    def test_modify_match_another_document(self):
        doc1 = self.Person(name="bob", age=10).save()
        doc2 = self.Person(name="jim", age=20).save()
        docs = [dict(doc1.to_mongo()), dict(doc2.to_mongo())]

        n_modified = doc1.modify({"name": doc2.name}, set__age=100)
        assert n_modified == 0

        self._assert_db_equal(docs)

    def test_modify_not_exists(self):
        doc1 = self.Person(name="bob", age=10).save()
        doc2 = self.Person(id=ObjectId(), name="jim", age=20)
        docs = [dict(doc1.to_mongo())]

        n_modified = doc2.modify({"name": doc2.name}, set__age=100)
        assert n_modified == 0

        self._assert_db_equal(docs)

    def test_modify_update(self):
        other_doc = self.Person(name="bob", age=10).save()
        doc = self.Person(
            name="jim", age=20, job=self.Job(name="10gen", years=3)
        ).save()

        doc_copy = doc._from_son(doc.to_mongo())

        # these changes must go away
        doc.name = "liza"
        doc.job.name = "Google"
        doc.job.years = 3

        n_modified = doc.modify(
            set__age=21, set__job__name="MongoDB", unset__job__years=True
        )
        assert n_modified == 1
        doc_copy.age = 21
        doc_copy.job.name = "MongoDB"
        del doc_copy.job.years

        assert doc.to_json() == doc_copy.to_json()
        assert doc._get_changed_fields() == []

        self._assert_db_equal([dict(other_doc.to_mongo()), dict(doc.to_mongo())])

    def test_modify_with_positional_push(self):
        class Content(EmbeddedDocument):
            keywords = ListField(StringField())

        class BlogPost(Document):
            tags = ListField(StringField())
            content = EmbeddedDocumentField(Content)

        post = BlogPost.objects.create(
            tags=["python"], content=Content(keywords=["ipsum"])
        )

        assert post.tags == ["python"]
        post.modify(push__tags__0=["code", "mongo"])
        assert post.tags == ["code", "mongo", "python"]

        # Assert same order of the list items is maintained in the db
        assert BlogPost._get_collection().find_one({"_id": post.pk})["tags"] == [
            "code",
            "mongo",
            "python",
        ]

        assert post.content.keywords == ["ipsum"]
        post.modify(push__content__keywords__0=["lorem"])
        assert post.content.keywords == ["lorem", "ipsum"]

        # Assert same order of the list items is maintained in the db
        assert BlogPost._get_collection().find_one({"_id": post.pk})["content"][
            "keywords"
        ] == ["lorem", "ipsum"]

    def test_save(self):
        """Ensure that a document may be saved in the database."""

        # Create person object and save it to the database
        person = self.Person(name="Test User", age=30)
        person.save()

        # Ensure that the object is in the database
        raw_doc = get_as_pymongo(person)
        assert raw_doc == {
            "_cls": "Person",
            "name": "Test User",
            "age": 30,
            "_id": person.id,
        }

    def test_save_write_concern(self):
        class Recipient(Document):
            email = EmailField(required=True)

        rec = Recipient(email="garbage@garbage.com")

        fn = Mock()
        rec._save_create = fn
        rec.save(write_concern={"w": 0})
        assert fn.call_args[1]["write_concern"] == {"w": 0}

    def test_save_skip_validation(self):
        class Recipient(Document):
            email = EmailField(required=True)

        recipient = Recipient(email="not-an-email")
        with pytest.raises(ValidationError):
            recipient.save()

        recipient.save(validate=False)
        raw_doc = get_as_pymongo(recipient)
        assert raw_doc == {"email": "not-an-email", "_id": recipient.id}

    def test_save_with_bad_id(self):
        class Clown(Document):
            id = IntField(primary_key=True)

        with pytest.raises(ValidationError):
            Clown(id="not_an_int").save()

    def test_save_to_a_value_that_equates_to_false(self):
        class Thing(EmbeddedDocument):
            count = IntField()

        class User(Document):
            thing = EmbeddedDocumentField(Thing)

        User.drop_collection()

        user = User(thing=Thing(count=1))
        user.save()
        user.reload()

        user.thing.count = 0
        user.save()

        user.reload()
        assert user.thing.count == 0

    def test_save_max_recursion_not_hit(self):
        class Person(Document):
            name = StringField()
            parent = ReferenceField("self")
            friend = ReferenceField("self")

        Person.drop_collection()

        p1 = Person(name="Wilson Snr")
        p1.parent = None
        p1.save()

        p2 = Person(name="Wilson Jr")
        p2.parent = p1
        p2.save()

        p1.friend = p2
        p1.save()

        # Confirm can save and it resets the changed fields without hitting
        # max recursion error
        p0 = Person.objects.first()
        p0.name = "wpjunior"
        p0.save()

    def test_save_max_recursion_not_hit_with_file_field(self):
        class Foo(Document):
            name = StringField()
            picture = FileField()
            bar = ReferenceField("self")

        Foo.drop_collection()

        a = Foo(name="hello").save()

        a.bar = a
        with open(TEST_IMAGE_PATH, "rb") as test_image:
            a.picture = test_image
            a.save()

            # Confirm can save and it resets the changed fields without hitting
            # max recursion error
            b = Foo.objects.with_id(a.id)
            b.name = "world"
            b.save()

            assert b.picture == b.bar.picture, b.bar.bar.picture

    def test_save_cascades(self):
        class Person(Document):
            name = StringField()
            parent = ReferenceField("self")

        Person.drop_collection()

        p1 = Person(name="Wilson Snr")
        p1.parent = None
        p1.save()

        p2 = Person(name="Wilson Jr")
        p2.parent = p1
        p2.save()

        p = Person.objects(name="Wilson Jr").get()
        p.parent.name = "Daddy Wilson"
        p.save(cascade=True)

        p1.reload()
        assert p1.name == p.parent.name

    def test_save_cascade_kwargs(self):
        class Person(Document):
            name = StringField()
            parent = ReferenceField("self")

        Person.drop_collection()

        p1 = Person(name="Wilson Snr")
        p1.parent = None
        p1.save()

        p2 = Person(name="Wilson Jr")
        p2.parent = p1
        p1.name = "Daddy Wilson"
        p2.save(force_insert=True, cascade_kwargs={"force_insert": False})

        p1.reload()
        p2.reload()
        assert p1.name == p2.parent.name

    def test_save_cascade_meta_false(self):
        class Person(Document):
            name = StringField()
            parent = ReferenceField("self")

            meta = {"cascade": False}

        Person.drop_collection()

        p1 = Person(name="Wilson Snr")
        p1.parent = None
        p1.save()

        p2 = Person(name="Wilson Jr")
        p2.parent = p1
        p2.save()

        p = Person.objects(name="Wilson Jr").get()
        p.parent.name = "Daddy Wilson"
        p.save()

        p1.reload()
        assert p1.name != p.parent.name

        p.save(cascade=True)
        p1.reload()
        assert p1.name == p.parent.name

    def test_save_cascade_meta_true(self):
        class Person(Document):
            name = StringField()
            parent = ReferenceField("self")

            meta = {"cascade": False}

        Person.drop_collection()

        p1 = Person(name="Wilson Snr")
        p1.parent = None
        p1.save()

        p2 = Person(name="Wilson Jr")
        p2.parent = p1
        p2.save(cascade=True)

        p = Person.objects(name="Wilson Jr").get()
        p.parent.name = "Daddy Wilson"
        p.save()

        p1.reload()
        assert p1.name != p.parent.name

    def test_save_cascades_generically(self):
        class Person(Document):
            name = StringField()
            parent = GenericReferenceField()

        Person.drop_collection()

        p1 = Person(name="Wilson Snr")
        p1.save()

        p2 = Person(name="Wilson Jr")
        p2.parent = p1
        p2.save()

        p = Person.objects(name="Wilson Jr").get()
        p.parent.name = "Daddy Wilson"
        p.save()

        p1.reload()
        assert p1.name != p.parent.name

        p.save(cascade=True)
        p1.reload()
        assert p1.name == p.parent.name

    def test_save_atomicity_condition(self):
        class Widget(Document):
            toggle = BooleanField(default=False)
            count = IntField(default=0)
            save_id = UUIDField()

        def flip(widget):
            widget.toggle = not widget.toggle
            widget.count += 1

        def UUID(i):
            return uuid.UUID(int=i)

        Widget.drop_collection()

        w1 = Widget(toggle=False, save_id=UUID(1))

        # ignore save_condition on new record creation
        w1.save(save_condition={"save_id": UUID(42)})
        w1.reload()
        assert not w1.toggle
        assert w1.save_id == UUID(1)
        assert w1.count == 0

        # mismatch in save_condition prevents save and raise exception
        flip(w1)
        assert w1.toggle
        assert w1.count == 1
        with pytest.raises(SaveConditionError):
            w1.save(save_condition={"save_id": UUID(42)})
        w1.reload()
        assert not w1.toggle
        assert w1.count == 0

        # matched save_condition allows save
        flip(w1)
        assert w1.toggle
        assert w1.count == 1
        w1.save(save_condition={"save_id": UUID(1)})
        w1.reload()
        assert w1.toggle
        assert w1.count == 1

        # save_condition can be used to ensure atomic read & updates
        # i.e., prevent interleaved reads and writes from separate contexts
        w2 = Widget.objects.get()
        assert w1 == w2
        old_id = w1.save_id

        flip(w1)
        w1.save_id = UUID(2)
        w1.save(save_condition={"save_id": old_id})
        w1.reload()
        assert not w1.toggle
        assert w1.count == 2
        flip(w2)
        flip(w2)
        with pytest.raises(SaveConditionError):
            w2.save(save_condition={"save_id": old_id})
        w2.reload()
        assert not w2.toggle
        assert w2.count == 2

        # save_condition uses mongoengine-style operator syntax
        flip(w1)
        w1.save(save_condition={"count__lt": w1.count})
        w1.reload()
        assert w1.toggle
        assert w1.count == 3
        flip(w1)
        with pytest.raises(SaveConditionError):
            w1.save(save_condition={"count__gte": w1.count})
        w1.reload()
        assert w1.toggle
        assert w1.count == 3

    def test_save_update_selectively(self):
        class WildBoy(Document):
            age = IntField()
            name = StringField()

        WildBoy.drop_collection()

        WildBoy(age=12, name="John").save()

        boy1 = WildBoy.objects().first()
        boy2 = WildBoy.objects().first()

        boy1.age = 99
        boy1.save()
        boy2.name = "Bob"
        boy2.save()

        fresh_boy = WildBoy.objects().first()
        assert fresh_boy.age == 99
        assert fresh_boy.name == "Bob"

    def test_save_update_selectively_with_custom_pk(self):
        # Prevents regression of #2082
        class WildBoy(Document):
            pk_id = StringField(primary_key=True)
            age = IntField()
            name = StringField()

        WildBoy.drop_collection()

        WildBoy(pk_id="A", age=12, name="John").save()

        boy1 = WildBoy.objects().first()
        boy2 = WildBoy.objects().first()

        boy1.age = 99
        boy1.save()
        boy2.name = "Bob"
        boy2.save()

        fresh_boy = WildBoy.objects().first()
        assert fresh_boy.age == 99
        assert fresh_boy.name == "Bob"

    def test_update(self):
        """Ensure that an existing document is updated instead of be
        overwritten.
        """
        # Create person object and save it to the database
        person = self.Person(name="Test User", age=30)
        person.save()

        # Create same person object, with same id, without age
        same_person = self.Person(name="Test")
        same_person.id = person.id
        same_person.save()

        # Confirm only one object
        assert self.Person.objects.count() == 1

        # reload
        person.reload()
        same_person.reload()

        # Confirm the same
        assert person == same_person
        assert person.name == same_person.name
        assert person.age == same_person.age

        # Confirm the saved values
        assert person.name == "Test"
        assert person.age == 30

        # Test only / exclude only updates included fields
        person = self.Person.objects.only("name").get()
        person.name = "User"
        person.save()

        person.reload()
        assert person.name == "User"
        assert person.age == 30

        # test exclude only updates set fields
        person = self.Person.objects.exclude("name").get()
        person.age = 21
        person.save()

        person.reload()
        assert person.name == "User"
        assert person.age == 21

        # Test only / exclude can set non excluded / included fields
        person = self.Person.objects.only("name").get()
        person.name = "Test"
        person.age = 30
        person.save()

        person.reload()
        assert person.name == "Test"
        assert person.age == 30

        # test exclude only updates set fields
        person = self.Person.objects.exclude("name").get()
        person.name = "User"
        person.age = 21
        person.save()

        person.reload()
        assert person.name == "User"
        assert person.age == 21

        # Confirm does remove unrequired fields
        person = self.Person.objects.exclude("name").get()
        person.age = None
        person.save()

        person.reload()
        assert person.name == "User"
        assert person.age is None

        person = self.Person.objects.get()
        person.name = None
        person.age = None
        person.save()

        person.reload()
        assert person.name is None
        assert person.age is None

    def test_update_rename_operator(self):
        """Test the $rename operator."""
        coll = self.Person._get_collection()
        doc = self.Person(name="John").save()
        raw_doc = coll.find_one({"_id": doc.pk})
        assert set(raw_doc.keys()) == {"_id", "_cls", "name"}

        doc.update(rename__name="first_name")
        raw_doc = coll.find_one({"_id": doc.pk})
        assert set(raw_doc.keys()) == {"_id", "_cls", "first_name"}
        assert raw_doc["first_name"] == "John"

    def test_inserts_if_you_set_the_pk(self):
        _ = self.Person(name="p1", id=bson.ObjectId()).save()
        p2 = self.Person(name="p2")
        p2.id = bson.ObjectId()
        p2.save()

        assert 2 == self.Person.objects.count()

    def test_can_save_if_not_included(self):
        class EmbeddedDoc(EmbeddedDocument):
            pass

        class Simple(Document):
            pass

        class Doc(Document):
            string_field = StringField(default="1")
            int_field = IntField(default=1)
            float_field = FloatField(default=1.1)
            boolean_field = BooleanField(default=True)
            datetime_field = DateTimeField(default=datetime.now)
            embedded_document_field = EmbeddedDocumentField(
                EmbeddedDoc, default=lambda: EmbeddedDoc()
            )
            list_field = ListField(default=lambda: [1, 2, 3])
            dict_field = DictField(default=lambda: {"hello": "world"})
            objectid_field = ObjectIdField(default=bson.ObjectId)
            reference_field = ReferenceField(Simple, default=lambda: Simple().save())
            map_field = MapField(IntField(), default=lambda: {"simple": 1})
            decimal_field = DecimalField(default=1.0)
            complex_datetime_field = ComplexDateTimeField(default=datetime.now)
            url_field = URLField(default="http://mongoengine.org")
            dynamic_field = DynamicField(default=1)
            generic_reference_field = GenericReferenceField(
                default=lambda: Simple().save()
            )
            sorted_list_field = SortedListField(IntField(), default=lambda: [1, 2, 3])
            email_field = EmailField(default="ross@example.com")
            geo_point_field = GeoPointField(default=lambda: [1, 2])
            sequence_field = SequenceField()
            uuid_field = UUIDField(default=uuid.uuid4)
            generic_embedded_document_field = GenericEmbeddedDocumentField(
                default=lambda: EmbeddedDoc()
            )

        Simple.drop_collection()
        Doc.drop_collection()

        Doc().save()
        my_doc = Doc.objects.only("string_field").first()
        my_doc.string_field = "string"
        my_doc.save()

        my_doc = Doc.objects.get(string_field="string")
        assert my_doc.string_field == "string"
        assert my_doc.int_field == 1

    def test_document_update(self):
        # try updating a non-saved document
        with pytest.raises(OperationError):
            person = self.Person(name="dcrosta")
            person.update(set__name="Dan Crosta")

        author = self.Person(name="dcrosta")
        author.save()

        author.update(set__name="Dan Crosta")
        author.reload()

        p1 = self.Person.objects.first()
        assert p1.name == author.name

        # try sending an empty update
        with pytest.raises(OperationError):
            person = self.Person.objects.first()
            person.update()

        # update that doesn't explicitly specify an operator should default
        # to 'set__'
        person = self.Person.objects.first()
        person.update(name="Dan")
        person.reload()
        assert "Dan" == person.name

    def test_update_unique_field(self):
        class Doc(Document):
            name = StringField(unique=True)

        doc1 = Doc(name="first").save()
        doc2 = Doc(name="second").save()

        with pytest.raises(NotUniqueError):
            doc2.update(set__name=doc1.name)

    def test_embedded_update(self):
        """Test update on `EmbeddedDocumentField` fields."""

        class Page(EmbeddedDocument):
            log_message = StringField(verbose_name="Log message", required=True)

        class Site(Document):
            page = EmbeddedDocumentField(Page)

        Site.drop_collection()
        site = Site(page=Page(log_message="Warning: Dummy message"))
        site.save()

        # Update
        site = Site.objects.first()
        site.page.log_message = "Error: Dummy message"
        site.save()

        site = Site.objects.first()
        assert site.page.log_message == "Error: Dummy message"

    def test_update_list_field(self):
        """Test update on `ListField` with $pull + $in."""

        class Doc(Document):
            foo = ListField(StringField())

        Doc.drop_collection()
        doc = Doc(foo=["a", "b", "c"])
        doc.save()

        # Update
        doc = Doc.objects.first()
        doc.update(pull__foo__in=["a", "c"])

        doc = Doc.objects.first()
        assert doc.foo == ["b"]

    def test_embedded_update_db_field(self):
        """Test update on `EmbeddedDocumentField` fields when db_field
        is other than default.
        """

        class Page(EmbeddedDocument):
            log_message = StringField(
                verbose_name="Log message", db_field="page_log_message", required=True
            )

        class Site(Document):
            page = EmbeddedDocumentField(Page)

        Site.drop_collection()

        site = Site(page=Page(log_message="Warning: Dummy message"))
        site.save()

        # Update
        site = Site.objects.first()
        site.page.log_message = "Error: Dummy message"
        site.save()

        site = Site.objects.first()
        assert site.page.log_message == "Error: Dummy message"

    def test_save_only_changed_fields(self):
        """Ensure save only sets / unsets changed fields."""

        class User(self.Person):
            active = BooleanField(default=True)

        User.drop_collection()

        # Create person object and save it to the database
        user = User(name="Test User", age=30, active=True)
        user.save()
        user.reload()

        # Simulated Race condition
        same_person = self.Person.objects.get()
        same_person.active = False

        user.age = 21
        user.save()

        same_person.name = "User"
        same_person.save()

        person = self.Person.objects.get()
        assert person.name == "User"
        assert person.age == 21
        assert person.active is False

    def test__get_changed_fields_same_ids_reference_field_does_not_enters_infinite_loop_embedded_doc(
        self,
    ):
        # Refers to Issue #1685
        class EmbeddedChildModel(EmbeddedDocument):
            id = DictField(primary_key=True)

        class ParentModel(Document):
            child = EmbeddedDocumentField(EmbeddedChildModel)

        emb = EmbeddedChildModel(id={"1": [1]})
        changed_fields = ParentModel(child=emb)._get_changed_fields()
        assert changed_fields == []

    def test__get_changed_fields_same_ids_reference_field_does_not_enters_infinite_loop_different_doc(
        self,
    ):
        # Refers to Issue #1685
        class User(Document):
            id = IntField(primary_key=True)
            name = StringField()

        class Message(Document):
            id = IntField(primary_key=True)
            author = ReferenceField(User)

        Message.drop_collection()

        # All objects share the same id, but each in a different collection
        user = User(id=1, name="user-name").save()
        message = Message(id=1, author=user).save()

        message.author.name = "tutu"
        assert message._get_changed_fields() == []
        assert user._get_changed_fields() == ["name"]

    def test__get_changed_fields_same_ids_embedded(self):
        # Refers to Issue #1768
        class User(EmbeddedDocument):
            id = IntField()
            name = StringField()

        class Message(Document):
            id = IntField(primary_key=True)
            author = EmbeddedDocumentField(User)

        Message.drop_collection()

        # All objects share the same id, but each in a different collection
        user = User(id=1, name="user-name")  # .save()
        message = Message(id=1, author=user).save()

        message.author.name = "tutu"
        assert message._get_changed_fields() == ["author.name"]
        message.save()

        message_fetched = Message.objects.with_id(message.id)
        assert message_fetched.author.name == "tutu"

    def test_query_count_when_saving(self):
        """Ensure references don't cause extra fetches when saving"""

        class Organization(Document):
            name = StringField()

        class User(Document):
            name = StringField()
            orgs = ListField(ReferenceField("Organization"))

        class Feed(Document):
            name = StringField()

        class UserSubscription(Document):
            name = StringField()
            user = ReferenceField(User)
            feed = ReferenceField(Feed)

        Organization.drop_collection()
        User.drop_collection()
        Feed.drop_collection()
        UserSubscription.drop_collection()

        o1 = Organization(name="o1").save()
        o2 = Organization(name="o2").save()

        u1 = User(name="Ross", orgs=[o1, o2]).save()
        f1 = Feed(name="MongoEngine").save()

        sub = UserSubscription(user=u1, feed=f1).save()

        user = User.objects.first()
        # Even if stored as ObjectId's internally mongoengine uses DBRefs
        # As ObjectId's aren't automatically dereferenced
        assert isinstance(user._data["orgs"][0], DBRef)
        assert isinstance(user.orgs[0], Organization)
        assert isinstance(user._data["orgs"][0], Organization)

        # Changing a value
        with query_counter() as q:
            assert q == 0
            sub = UserSubscription.objects.first()
            assert q == 1
            sub.name = "Test Sub"
            sub.save()
            assert q == 2

        # Changing a value that will cascade
        with query_counter() as q:
            assert q == 0
            sub = UserSubscription.objects.first()
            assert q == 1
            sub.user.name = "Test"
            assert q == 2
            sub.save(cascade=True)
            assert q == 3

        # Changing a value and one that will cascade
        with query_counter() as q:
            assert q == 0
            sub = UserSubscription.objects.first()
            sub.name = "Test Sub 2"
            assert q == 1
            sub.user.name = "Test 2"
            assert q == 2
            sub.save(cascade=True)
            assert q == 4  # One for the UserSub and one for the User

        # Saving with just the refs
        with query_counter() as q:
            assert q == 0
            sub = UserSubscription(user=u1.pk, feed=f1.pk)
            assert q == 0
            sub.save()
            assert q == 1

        # Saving with just the refs on a ListField
        with query_counter() as q:
            assert q == 0
            User(name="Bob", orgs=[o1.pk, o2.pk]).save()
            assert q == 1

        # Saving new objects
        with query_counter() as q:
            assert q == 0
            user = User.objects.first()
            assert q == 1
            feed = Feed.objects.first()
            assert q == 2
            sub = UserSubscription(user=user, feed=feed)
            assert q == 2  # Check no change
            sub.save()
            assert q == 3

    def test_set_unset_one_operation(self):
        """Ensure that $set and $unset actions are performed in the
        same operation.
        """

        class FooBar(Document):
            foo = StringField(default=None)
            bar = StringField(default=None)

        FooBar.drop_collection()

        # write an entity with a single prop
        foo = FooBar(foo="foo").save()

        assert foo.foo == "foo"
        del foo.foo
        foo.bar = "bar"

        with query_counter() as q:
            assert 0 == q
            foo.save()
            assert 1 == q

    def test_save_only_changed_fields_recursive(self):
        """Ensure save only sets / unsets changed fields."""

        class Comment(EmbeddedDocument):
            published = BooleanField(default=True)

        class User(self.Person):
            comments_dict = DictField()
            comments = ListField(EmbeddedDocumentField(Comment))
            active = BooleanField(default=True)

        User.drop_collection()

        # Create person object and save it to the database
        person = User(name="Test User", age=30, active=True)
        person.comments.append(Comment())
        person.save()
        person.reload()

        person = self.Person.objects.get()
        assert person.comments[0].published

        person.comments[0].published = False
        person.save()

        person = self.Person.objects.get()
        assert not person.comments[0].published

        # Simple dict w
        person.comments_dict["first_post"] = Comment()
        person.save()

        person = self.Person.objects.get()
        assert person.comments_dict["first_post"].published

        person.comments_dict["first_post"].published = False
        person.save()

        person = self.Person.objects.get()
        assert not person.comments_dict["first_post"].published

    def test_delete(self):
        """Ensure that document may be deleted using the delete method."""
        person = self.Person(name="Test User", age=30)
        person.save()
        assert self.Person.objects.count() == 1
        person.delete()
        assert self.Person.objects.count() == 0

    def test_save_custom_id(self):
        """Ensure that a document may be saved with a custom _id."""

        # Create person object and save it to the database
        person = self.Person(name="Test User", age=30, id="497ce96f395f2f052a494fd4")
        person.save()

        # Ensure that the object is in the database with the correct _id
        collection = self.db[self.Person._get_collection_name()]
        person_obj = collection.find_one({"name": "Test User"})
        assert str(person_obj["_id"]) == "497ce96f395f2f052a494fd4"

    def test_save_custom_pk(self):
        """Ensure that a document may be saved with a custom _id using
        pk alias.
        """
        # Create person object and save it to the database
        person = self.Person(name="Test User", age=30, pk="497ce96f395f2f052a494fd4")
        person.save()

        # Ensure that the object is in the database with the correct _id
        collection = self.db[self.Person._get_collection_name()]
        person_obj = collection.find_one({"name": "Test User"})
        assert str(person_obj["_id"]) == "497ce96f395f2f052a494fd4"

    def test_save_list(self):
        """Ensure that a list field may be properly saved."""

        class Comment(EmbeddedDocument):
            content = StringField()

        class BlogPost(Document):
            content = StringField()
            comments = ListField(EmbeddedDocumentField(Comment))
            tags = ListField(StringField())

        BlogPost.drop_collection()

        post = BlogPost(content="Went for a walk today...")
        post.tags = tags = ["fun", "leisure"]
        comments = [Comment(content="Good for you"), Comment(content="Yay.")]
        post.comments = comments
        post.save()

        collection = self.db[BlogPost._get_collection_name()]
        post_obj = collection.find_one()
        assert post_obj["tags"] == tags
        for comment_obj, comment in zip(post_obj["comments"], comments):
            assert comment_obj["content"] == comment["content"]

    def test_list_search_by_embedded(self):
        class User(Document):
            username = StringField(required=True)

            meta = {"allow_inheritance": False}

        class Comment(EmbeddedDocument):
            comment = StringField()
            user = ReferenceField(User, required=True)

            meta = {"allow_inheritance": False}

        class Page(Document):
            comments = ListField(EmbeddedDocumentField(Comment))
            meta = {
                "allow_inheritance": False,
                "indexes": [{"fields": ["comments.user"]}],
            }

        User.drop_collection()
        Page.drop_collection()

        u1 = User(username="wilson")
        u1.save()

        u2 = User(username="rozza")
        u2.save()

        u3 = User(username="hmarr")
        u3.save()

        p1 = Page(
            comments=[
                Comment(user=u1, comment="Its very good"),
                Comment(user=u2, comment="Hello world"),
                Comment(user=u3, comment="Ping Pong"),
                Comment(user=u1, comment="I like a beer"),
            ]
        )
        p1.save()

        p2 = Page(
            comments=[
                Comment(user=u1, comment="Its very good"),
                Comment(user=u2, comment="Hello world"),
            ]
        )
        p2.save()

        p3 = Page(comments=[Comment(user=u3, comment="Its very good")])
        p3.save()

        p4 = Page(comments=[Comment(user=u2, comment="Heavy Metal song")])
        p4.save()

        assert [p1, p2] == list(Page.objects.filter(comments__user=u1))
        assert [p1, p2, p4] == list(Page.objects.filter(comments__user=u2))
        assert [p1, p3] == list(Page.objects.filter(comments__user=u3))

    def test_save_embedded_document(self):
        """Ensure that a document with an embedded document field may
        be saved in the database.
        """

        class EmployeeDetails(EmbeddedDocument):
            position = StringField()

        class Employee(self.Person):
            salary = IntField()
            details = EmbeddedDocumentField(EmployeeDetails)

        # Create employee object and save it to the database
        employee = Employee(name="Test Employee", age=50, salary=20000)
        employee.details = EmployeeDetails(position="Developer")
        employee.save()

        # Ensure that the object is in the database
        collection = self.db[self.Person._get_collection_name()]
        employee_obj = collection.find_one({"name": "Test Employee"})
        assert employee_obj["name"] == "Test Employee"
        assert employee_obj["age"] == 50

        # Ensure that the 'details' embedded object saved correctly
        assert employee_obj["details"]["position"] == "Developer"

    def test_embedded_update_after_save(self):
        """Test update of `EmbeddedDocumentField` attached to a newly
        saved document.
        """

        class Page(EmbeddedDocument):
            log_message = StringField(verbose_name="Log message", required=True)

        class Site(Document):
            page = EmbeddedDocumentField(Page)

        Site.drop_collection()
        site = Site(page=Page(log_message="Warning: Dummy message"))
        site.save()

        # Update
        site.page.log_message = "Error: Dummy message"
        site.save()

        site = Site.objects.first()
        assert site.page.log_message == "Error: Dummy message"

    def test_updating_an_embedded_document(self):
        """Ensure that a document with an embedded document field may
        be saved in the database.
        """

        class EmployeeDetails(EmbeddedDocument):
            position = StringField()

        class Employee(self.Person):
            salary = IntField()
            details = EmbeddedDocumentField(EmployeeDetails)

        # Create employee object and save it to the database
        employee = Employee(name="Test Employee", age=50, salary=20000)
        employee.details = EmployeeDetails(position="Developer")
        employee.save()

        # Test updating an embedded document
        promoted_employee = Employee.objects.get(name="Test Employee")
        promoted_employee.details.position = "Senior Developer"
        promoted_employee.save()

        promoted_employee.reload()
        assert promoted_employee.name == "Test Employee"
        assert promoted_employee.age == 50

        # Ensure that the 'details' embedded object saved correctly
        assert promoted_employee.details.position == "Senior Developer"

        # Test removal
        promoted_employee.details = None
        promoted_employee.save()

        promoted_employee.reload()
        assert promoted_employee.details is None

    def test_object_mixins(self):
        class NameMixin:
            name = StringField()

        class Foo(EmbeddedDocument, NameMixin):
            quantity = IntField()

        assert ["name", "quantity"] == sorted(Foo._fields.keys())

        class Bar(Document, NameMixin):
            widgets = StringField()

        assert ["id", "name", "widgets"] == sorted(Bar._fields.keys())

    def test_mixin_inheritance(self):
        class BaseMixIn:
            count = IntField()
            data = StringField()

        class DoubleMixIn(BaseMixIn):
            comment = StringField()

        class TestDoc(Document, DoubleMixIn):
            age = IntField()

        TestDoc.drop_collection()
        t = TestDoc(count=12, data="test", comment="great!", age=19)

        t.save()

        t = TestDoc.objects.first()

        assert t.age == 19
        assert t.comment == "great!"
        assert t.data == "test"
        assert t.count == 12

    def test_save_reference(self):
        """Ensure that a document reference field may be saved in the
        database.
        """

        class BlogPost(Document):
            meta = {"collection": "blogpost_1"}
            content = StringField()
            author = ReferenceField(self.Person)

        BlogPost.drop_collection()

        author = self.Person(name="Test User")
        author.save()

        post = BlogPost(content="Watched some TV today... how exciting.")
        # Should only reference author when saving
        post.author = author
        post.save()

        post_obj = BlogPost.objects.first()

        # Test laziness
        assert isinstance(post_obj._data["author"], bson.DBRef)
        assert isinstance(post_obj.author, self.Person)
        assert post_obj.author.name == "Test User"

        # Ensure that the dereferenced object may be changed and saved
        post_obj.author.age = 25
        post_obj.author.save()

        author = list(self.Person.objects(name="Test User"))[-1]
        assert author.age == 25

    def test_duplicate_db_fields_raise_invalid_document_error(self):
        """Ensure a InvalidDocumentError is thrown if duplicate fields
        declare the same db_field.
        """
        with pytest.raises(InvalidDocumentError):

            class Foo(Document):
                name = StringField()
                name2 = StringField(db_field="name")

    def test_invalid_son(self):
        """Raise an error if loading invalid data."""

        class Occurrence(EmbeddedDocument):
            number = IntField()

        class Word(Document):
            stem = StringField()
            count = IntField(default=1)
            forms = ListField(StringField(), default=list)
            occurs = ListField(EmbeddedDocumentField(Occurrence), default=list)

        with pytest.raises(InvalidDocumentError):
            Word._from_son(
                {
                    "stem": [1, 2, 3],
                    "forms": 1,
                    "count": "one",
                    "occurs": {"hello": None},
                }
            )

        # Tests for issue #1438: https://github.com/MongoEngine/mongoengine/issues/1438
        with pytest.raises(ValueError):
            Word._from_son("this is not a valid SON dict")

    def test_reverse_delete_rule_cascade_and_nullify(self):
        """Ensure that a referenced document is also deleted upon
        deletion.
        """

        class BlogPost(Document):
            content = StringField()
            author = ReferenceField(self.Person, reverse_delete_rule=CASCADE)
            reviewer = ReferenceField(self.Person, reverse_delete_rule=NULLIFY)

        self.Person.drop_collection()
        BlogPost.drop_collection()

        author = self.Person(name="Test User")
        author.save()

        reviewer = self.Person(name="Re Viewer")
        reviewer.save()

        post = BlogPost(content="Watched some TV")
        post.author = author
        post.reviewer = reviewer
        post.save()

        reviewer.delete()
        # No effect on the BlogPost
        assert BlogPost.objects.count() == 1
        assert BlogPost.objects.get().reviewer is None

        # Delete the Person, which should lead to deletion of the BlogPost, too
        author.delete()
        assert BlogPost.objects.count() == 0

    def test_reverse_delete_rule_pull(self):
        """Ensure that a referenced document is also deleted with
        pull.
        """

        class Record(Document):
            name = StringField()
            children = ListField(ReferenceField("self", reverse_delete_rule=PULL))

        Record.drop_collection()

        parent_record = Record(name="parent").save()
        child_record = Record(name="child").save()
        parent_record.children.append(child_record)
        parent_record.save()

        child_record.delete()
        assert Record.objects(name="parent").get().children == []

    def test_reverse_delete_rule_with_custom_id_field(self):
        """Ensure that a referenced document with custom primary key
        is also deleted upon deletion.
        """

        class User(Document):
            name = StringField(primary_key=True)

        class Book(Document):
            author = ReferenceField(User, reverse_delete_rule=CASCADE)
            reviewer = ReferenceField(User, reverse_delete_rule=NULLIFY)

        User.drop_collection()
        Book.drop_collection()

        user = User(name="Mike").save()
        reviewer = User(name="John").save()
        _ = Book(author=user, reviewer=reviewer).save()

        reviewer.delete()
        assert Book.objects.count() == 1
        assert Book.objects.get().reviewer is None

        user.delete()
        assert Book.objects.count() == 0

    def test_reverse_delete_rule_with_shared_id_among_collections(self):
        """Ensure that cascade delete rule doesn't mix id among
        collections.
        """

        class User(Document):
            id = IntField(primary_key=True)

        class Book(Document):
            id = IntField(primary_key=True)
            author = ReferenceField(User, reverse_delete_rule=CASCADE)

        User.drop_collection()
        Book.drop_collection()

        user_1 = User(id=1).save()
        user_2 = User(id=2).save()
        _ = Book(id=1, author=user_2).save()
        book_2 = Book(id=2, author=user_1).save()

        user_2.delete()
        # Deleting user_2 should also delete book_1 but not book_2
        assert Book.objects.count() == 1
        assert Book.objects.get() == book_2

        user_3 = User(id=3).save()
        _ = Book(id=3, author=user_3).save()

        user_3.delete()
        # Deleting user_3 should also delete book_3
        assert Book.objects.count() == 1
        assert Book.objects.get() == book_2

    def test_reverse_delete_rule_with_document_inheritance(self):
        """Ensure that a referenced document is also deleted upon
        deletion of a child document.
        """

        class Writer(self.Person):
            pass

        class BlogPost(Document):
            content = StringField()
            author = ReferenceField(self.Person, reverse_delete_rule=CASCADE)
            reviewer = ReferenceField(self.Person, reverse_delete_rule=NULLIFY)

        self.Person.drop_collection()
        BlogPost.drop_collection()

        author = Writer(name="Test User")
        author.save()

        reviewer = Writer(name="Re Viewer")
        reviewer.save()

        post = BlogPost(content="Watched some TV")
        post.author = author
        post.reviewer = reviewer
        post.save()

        reviewer.delete()
        assert BlogPost.objects.count() == 1
        assert BlogPost.objects.get().reviewer is None

        # Delete the Writer should lead to deletion of the BlogPost
        author.delete()
        assert BlogPost.objects.count() == 0

    def test_reverse_delete_rule_cascade_and_nullify_complex_field(self):
        """Ensure that a referenced document is also deleted upon
        deletion for complex fields.
        """

        class BlogPost(Document):
            content = StringField()
            authors = ListField(
                ReferenceField(self.Person, reverse_delete_rule=CASCADE)
            )
            reviewers = ListField(
                ReferenceField(self.Person, reverse_delete_rule=NULLIFY)
            )

        self.Person.drop_collection()
        BlogPost.drop_collection()

        author = self.Person(name="Test User")
        author.save()

        reviewer = self.Person(name="Re Viewer")
        reviewer.save()

        post = BlogPost(content="Watched some TV")
        post.authors = [author]
        post.reviewers = [reviewer]
        post.save()

        # Deleting the reviewer should have no effect on the BlogPost
        reviewer.delete()
        assert BlogPost.objects.count() == 1
        assert BlogPost.objects.get().reviewers == []

        # Delete the Person, which should lead to deletion of the BlogPost, too
        author.delete()
        assert BlogPost.objects.count() == 0

    def test_reverse_delete_rule_cascade_triggers_pre_delete_signal(self):
        """Ensure the pre_delete signal is triggered upon a cascading
        deletion setup a blog post with content, an author and editor
        delete the author which triggers deletion of blogpost via
        cascade blog post's pre_delete signal alters an editor attribute.
        """

        class Editor(self.Person):
            review_queue = IntField(default=0)

        class BlogPost(Document):
            content = StringField()
            author = ReferenceField(self.Person, reverse_delete_rule=CASCADE)
            editor = ReferenceField(Editor)

            @classmethod
            def pre_delete(cls, sender, document, **kwargs):
                # decrement the docs-to-review count
                document.editor.update(dec__review_queue=1)

        signals.pre_delete.connect(BlogPost.pre_delete, sender=BlogPost)

        self.Person.drop_collection()
        BlogPost.drop_collection()
        Editor.drop_collection()

        author = self.Person(name="Will S.").save()
        editor = Editor(name="Max P.", review_queue=1).save()
        BlogPost(content="wrote some books", author=author, editor=editor).save()

        # delete the author, the post is also deleted due to the CASCADE rule
        author.delete()

        # the pre-delete signal should have decremented the editor's queue
        editor = Editor.objects(name="Max P.").get()
        assert editor.review_queue == 0

    def test_two_way_reverse_delete_rule(self):
        """Ensure that Bi-Directional relationships work with
        reverse_delete_rule
        """

        class Bar(Document):
            content = StringField()
            foo = ReferenceField("Foo")

        class Foo(Document):
            content = StringField()
            bar = ReferenceField(Bar)

        Bar.register_delete_rule(Foo, "bar", NULLIFY)
        Foo.register_delete_rule(Bar, "foo", NULLIFY)

        Bar.drop_collection()
        Foo.drop_collection()

        b = Bar(content="Hello")
        b.save()

        f = Foo(content="world", bar=b)
        f.save()

        b.foo = f
        b.save()

        f.delete()

        assert Bar.objects.count() == 1  # No effect on the BlogPost
        assert Bar.objects.get().foo is None

    def test_invalid_reverse_delete_rule_raise_errors(self):
        with pytest.raises(InvalidDocumentError):

            class Blog(Document):
                content = StringField()
                authors = MapField(
                    ReferenceField(self.Person, reverse_delete_rule=CASCADE)
                )
                reviewers = DictField(
                    field=ReferenceField(self.Person, reverse_delete_rule=NULLIFY)
                )

        with pytest.raises(InvalidDocumentError):

            class Parents(EmbeddedDocument):
                father = ReferenceField("Person", reverse_delete_rule=DENY)
                mother = ReferenceField("Person", reverse_delete_rule=DENY)

    def test_reverse_delete_rule_cascade_recurs(self):
        """Ensure that a chain of documents is also deleted upon
        cascaded deletion.
        """

        class BlogPost(Document):
            content = StringField()
            author = ReferenceField(self.Person, reverse_delete_rule=CASCADE)

        class Comment(Document):
            text = StringField()
            post = ReferenceField(BlogPost, reverse_delete_rule=CASCADE)

        self.Person.drop_collection()
        BlogPost.drop_collection()
        Comment.drop_collection()

        author = self.Person(name="Test User")
        author.save()

        post = BlogPost(content="Watched some TV")
        post.author = author
        post.save()

        comment = Comment(text="Kudos.")
        comment.post = post
        comment.save()

        # Delete the Person, which should lead to deletion of the BlogPost,
        # and, recursively to the Comment, too
        author.delete()
        assert Comment.objects.count() == 0

    def test_reverse_delete_rule_deny(self):
        """Ensure that a document cannot be referenced if there are
        still documents referring to it.
        """

        class BlogPost(Document):
            content = StringField()
            author = ReferenceField(self.Person, reverse_delete_rule=DENY)

        self.Person.drop_collection()
        BlogPost.drop_collection()

        author = self.Person(name="Test User")
        author.save()

        post = BlogPost(content="Watched some TV")
        post.author = author
        post.save()

        # Delete the Person should be denied
        with pytest.raises(OperationError):
            author.delete()  # Should raise denied error
        assert BlogPost.objects.count() == 1  # No objects may have been deleted
        assert self.Person.objects.count() == 1

        # Other users, that don't have BlogPosts must be removable, like normal
        author = self.Person(name="Another User")
        author.save()

        assert self.Person.objects.count() == 2
        author.delete()
        assert self.Person.objects.count() == 1

    def test_lazy_delete_rules(self):
        """Ensure that a document does not need to be defined to reference it
        in a ReferenceField."""

        assert not _undefined_document_delete_rules.get("BlogPostLazy")

        # named "lazy" to ensure these Documents don't exist in the
        # document registry
        class CommentLazy(Document):
            text = StringField()
            post = ReferenceField("BlogPostLazy", reverse_delete_rule=CASCADE)

        assert len(_undefined_document_delete_rules.get("BlogPostLazy")) == 1

        class CommentDosLazy(Document):
            textdos = StringField()
            postdos = ReferenceField("BlogPostLazy", reverse_delete_rule=CASCADE)

        assert len(_undefined_document_delete_rules.get("BlogPostLazy")) == 2

        class BlogPostLazy(Document):
            content = StringField()
            author = ReferenceField(self.Person, reverse_delete_rule=CASCADE)

        assert not _undefined_document_delete_rules.get("BlogPostLazy")

        self.Person.drop_collection()
        BlogPostLazy.drop_collection()
        CommentLazy.drop_collection()

        author = self.Person(name="Test User")
        author.save()

        post = BlogPostLazy(content="Watched some TV")
        post.author = author
        post.save()

        comment = CommentLazy(text="Kudos.")
        comment.post = post
        comment.save()

        # Delete the Person, which should lead to deletion of the BlogPost,
        # and, recursively to the Comment, too
        author.delete()
        assert CommentLazy.objects.count() == 0

    def subclasses_and_unique_keys_works(self):
        class A(Document):
            pass

        class B(A):
            foo = BooleanField(unique=True)

        A.drop_collection()
        B.drop_collection()

        A().save()
        A().save()
        B(foo=True).save()

        assert A.objects.count() == 2
        assert B.objects.count() == 1

    def test_document_hash(self):
        """Test document in list, dict, set."""

        class User(Document):
            pass

        class BlogPost(Document):
            pass

        # Clear old data
        User.drop_collection()
        BlogPost.drop_collection()

        u1 = User.objects.create()
        u2 = User.objects.create()
        u3 = User.objects.create()
        u4 = User()  # New object

        b1 = BlogPost.objects.create()
        b2 = BlogPost.objects.create()

        # Make sure docs are properly identified in a list (__eq__ is used
        # for the comparison).
        all_user_list = list(User.objects.all())
        assert u1 in all_user_list
        assert u2 in all_user_list
        assert u3 in all_user_list
        assert u4 not in all_user_list  # New object
        assert b1 not in all_user_list  # Other object
        assert b2 not in all_user_list  # Other object

        # Make sure docs can be used as keys in a dict (__hash__ is used
        # for hashing the docs).
        all_user_dic = {}
        for u in User.objects.all():
            all_user_dic[u] = "OK"

        assert all_user_dic.get(u1, False) == "OK"
        assert all_user_dic.get(u2, False) == "OK"
        assert all_user_dic.get(u3, False) == "OK"
        assert all_user_dic.get(u4, False) is False  # New object
        assert all_user_dic.get(b1, False) is False  # Other object
        assert all_user_dic.get(b2, False) is False  # Other object

        # Make sure docs are properly identified in a set (__hash__ is used
        # for hashing the docs).
        all_user_set = set(User.objects.all())
        assert u1 in all_user_set
        assert u4 not in all_user_set
        assert b1 not in all_user_list
        assert b2 not in all_user_list

        # Make sure duplicate docs aren't accepted in the set
        assert len(all_user_set) == 3
        all_user_set.add(u1)
        all_user_set.add(u2)
        all_user_set.add(u3)
        assert len(all_user_set) == 3

    def test_picklable(self):
        pickle_doc = PickleTest(number=1, string="One", lists=["1", "2"])
        pickle_doc.embedded = PickleEmbedded()
        pickled_doc = pickle.dumps(
            pickle_doc
        )  # make sure pickling works even before the doc is saved
        pickle_doc.save()

        pickled_doc = pickle.dumps(pickle_doc)
        resurrected = pickle.loads(pickled_doc)

        assert resurrected == pickle_doc

        # Test pickling changed data
        pickle_doc.lists.append("3")
        pickled_doc = pickle.dumps(pickle_doc)
        resurrected = pickle.loads(pickled_doc)

        assert resurrected == pickle_doc
        resurrected.string = "Two"
        resurrected.save()

        pickle_doc = PickleTest.objects.first()
        assert resurrected == pickle_doc
        assert pickle_doc.string == "Two"
        assert pickle_doc.lists == ["1", "2", "3"]

    def test_regular_document_pickle(self):
        pickle_doc = PickleTest(number=1, string="One", lists=["1", "2"])
        pickled_doc = pickle.dumps(
            pickle_doc
        )  # make sure pickling works even before the doc is saved
        pickle_doc.save()

        pickled_doc = pickle.dumps(pickle_doc)

        # Test that when a document's definition changes the new
        # definition is used
        fixtures.PickleTest = fixtures.NewDocumentPickleTest

        resurrected = pickle.loads(pickled_doc)
        assert resurrected.__class__ == fixtures.NewDocumentPickleTest
        assert (
            resurrected._fields_ordered
            == fixtures.NewDocumentPickleTest._fields_ordered
        )
        assert resurrected._fields_ordered != pickle_doc._fields_ordered

        # The local PickleTest is still a ref to the original
        fixtures.PickleTest = PickleTest

    def test_dynamic_document_pickle(self):
        pickle_doc = PickleDynamicTest(
            name="test", number=1, string="One", lists=["1", "2"]
        )
        pickle_doc.embedded = PickleDynamicEmbedded(foo="Bar")
        pickled_doc = pickle.dumps(
            pickle_doc
        )  # make sure pickling works even before the doc is saved

        pickle_doc.save()

        pickled_doc = pickle.dumps(pickle_doc)
        resurrected = pickle.loads(pickled_doc)

        assert resurrected == pickle_doc
        assert resurrected._fields_ordered == pickle_doc._fields_ordered
        assert resurrected._dynamic_fields.keys() == pickle_doc._dynamic_fields.keys()

        assert resurrected.embedded == pickle_doc.embedded
        assert (
            resurrected.embedded._fields_ordered == pickle_doc.embedded._fields_ordered
        )
        assert (
            resurrected.embedded._dynamic_fields.keys()
            == pickle_doc.embedded._dynamic_fields.keys()
        )

    def test_picklable_on_signals(self):
        pickle_doc = PickleSignalsTest(number=1, string="One", lists=["1", "2"])
        pickle_doc.embedded = PickleEmbedded()
        pickle_doc.save()
        pickle_doc.delete()

    def test_override_method_with_field(self):
        """Test creating a field with a field name that would override
        the "validate" method.
        """
        with pytest.raises(InvalidDocumentError):

            class Blog(Document):
                validate = DictField()

    def test_mutating_documents(self):
        class B(EmbeddedDocument):
            field1 = StringField(default="field1")

        class A(Document):
            b = EmbeddedDocumentField(B, default=lambda: B())

        A.drop_collection()

        a = A()
        a.save()
        a.reload()
        assert a.b.field1 == "field1"

        class C(EmbeddedDocument):
            c_field = StringField(default="cfield")

        class B(EmbeddedDocument):
            field1 = StringField(default="field1")
            field2 = EmbeddedDocumentField(C, default=lambda: C())

        class A(Document):
            b = EmbeddedDocumentField(B, default=lambda: B())

        a = A.objects()[0]
        a.b.field2.c_field = "new value"
        a.save()

        a.reload()
        assert a.b.field2.c_field == "new value"

    def test_can_save_false_values(self):
        """Ensures you can save False values on save."""

        class Doc(Document):
            foo = StringField()
            archived = BooleanField(default=False, required=True)

        Doc.drop_collection()

        d = Doc()
        d.save()
        d.archived = False
        d.save()

        assert Doc.objects(archived=False).count() == 1

    def test_can_save_false_values_dynamic(self):
        """Ensures you can save False values on dynamic docs."""

        class Doc(DynamicDocument):
            foo = StringField()

        Doc.drop_collection()

        d = Doc()
        d.save()
        d.archived = False
        d.save()

        assert Doc.objects(archived=False).count() == 1

    def test_do_not_save_unchanged_references(self):
        """Ensures cascading saves dont auto update"""

        class Job(Document):
            name = StringField()

        class Person(Document):
            name = StringField()
            age = IntField()
            job = ReferenceField(Job)

        Job.drop_collection()
        Person.drop_collection()

        job = Job(name="Job 1")
        # job should not have any changed fields after the save
        job.save()

        person = Person(name="name", age=10, job=job)

        from pymongo.collection import Collection

        orig_update_one = Collection.update_one
        try:

            def fake_update_one(*args, **kwargs):
                self.fail("Unexpected update for %s" % args[0].name)
                return orig_update_one(*args, **kwargs)

            Collection.update_one = fake_update_one
            person.save()
        finally:
            Collection.update_one = orig_update_one

    def test_db_alias_tests(self):
        """DB Alias tests."""
        # mongoenginetest - Is default connection alias from setUp()
        # Register Aliases
        register_connection("testdb-1", "mongoenginetest2")
        register_connection("testdb-2", "mongoenginetest3")
        register_connection("testdb-3", "mongoenginetest4")

        class User(Document):
            name = StringField()
            meta = {"db_alias": "testdb-1"}

        class Book(Document):
            name = StringField()
            meta = {"db_alias": "testdb-2"}

        # Drops
        User.drop_collection()
        Book.drop_collection()

        # Create
        bob = User.objects.create(name="Bob")
        hp = Book.objects.create(name="Harry Potter")

        # Selects
        assert User.objects.first() == bob
        assert Book.objects.first() == hp

        # DeReference
        class AuthorBooks(Document):
            author = ReferenceField(User)
            book = ReferenceField(Book)
            meta = {"db_alias": "testdb-3"}

        # Drops
        AuthorBooks.drop_collection()

        ab = AuthorBooks.objects.create(author=bob, book=hp)

        # select
        assert AuthorBooks.objects.first() == ab
        assert AuthorBooks.objects.first().book == hp
        assert AuthorBooks.objects.first().author == bob
        assert AuthorBooks.objects.filter(author=bob).first() == ab
        assert AuthorBooks.objects.filter(book=hp).first() == ab

        # DB Alias
        assert User._get_db() == get_db("testdb-1")
        assert Book._get_db() == get_db("testdb-2")
        assert AuthorBooks._get_db() == get_db("testdb-3")

        # Collections
        assert User._get_collection() == get_db("testdb-1")[User._get_collection_name()]
        assert Book._get_collection() == get_db("testdb-2")[Book._get_collection_name()]
        assert (
            AuthorBooks._get_collection()
            == get_db("testdb-3")[AuthorBooks._get_collection_name()]
        )

    def test_db_alias_overrides(self):
        """Test db_alias can be overriden."""
        # Register a connection with db_alias testdb-2
        register_connection("testdb-2", "mongoenginetest2")

        class A(Document):
            """Uses default db_alias"""

            name = StringField()
            meta = {"allow_inheritance": True}

        class B(A):
            """Uses testdb-2 db_alias"""

            meta = {"db_alias": "testdb-2"}

        A.objects.all()

        assert "testdb-2" == B._meta.get("db_alias")
        assert "mongoenginetest" == A._get_collection().database.name
        assert "mongoenginetest2" == B._get_collection().database.name

    def test_db_alias_propagates(self):
        """db_alias propagates?"""
        register_connection("testdb-1", "mongoenginetest2")

        class A(Document):
            name = StringField()
            meta = {"db_alias": "testdb-1", "allow_inheritance": True}

        class B(A):
            pass

        assert "testdb-1" == B._meta.get("db_alias")

    def test_db_ref_usage(self):
        """DB Ref usage in dict_fields."""

        class User(Document):
            name = StringField()

        class Book(Document):
            name = StringField()
            author = ReferenceField(User)
            extra = DictField()
            meta = {"ordering": ["+name"]}

            def __unicode__(self):
                return self.name

            def __str__(self):
                return self.name

        # Drops
        User.drop_collection()
        Book.drop_collection()

        # Authors
        bob = User.objects.create(name="Bob")
        jon = User.objects.create(name="Jon")

        # Redactors
        karl = User.objects.create(name="Karl")
        susan = User.objects.create(name="Susan")
        peter = User.objects.create(name="Peter")

        # Bob
        Book.objects.create(
            name="1",
            author=bob,
            extra={"a": bob.to_dbref(), "b": [karl.to_dbref(), susan.to_dbref()]},
        )
        Book.objects.create(
            name="2", author=bob, extra={"a": bob.to_dbref(), "b": karl.to_dbref()}
        )
        Book.objects.create(
            name="3",
            author=bob,
            extra={"a": bob.to_dbref(), "c": [jon.to_dbref(), peter.to_dbref()]},
        )
        Book.objects.create(name="4", author=bob)

        # Jon
        Book.objects.create(name="5", author=jon)
        Book.objects.create(name="6", author=peter)
        Book.objects.create(name="7", author=jon)
        Book.objects.create(name="8", author=jon)
        Book.objects.create(name="9", author=jon, extra={"a": peter.to_dbref()})

        # Checks
        assert ",".join([str(b) for b in Book.objects.all()]) == "1,2,3,4,5,6,7,8,9"
        # bob related books
        bob_books_qs = Book.objects.filter(
            Q(extra__a=bob) | Q(author=bob) | Q(extra__b=bob)
        )
        assert [str(b) for b in bob_books_qs] == ["1", "2", "3", "4"]
        assert bob_books_qs.count() == 4

        # Susan & Karl related books
        susan_karl_books_qs = Book.objects.filter(
            Q(extra__a__all=[karl, susan])
            | Q(author__all=[karl, susan])
            | Q(extra__b__all=[karl.to_dbref(), susan.to_dbref()])
        )
        assert [str(b) for b in susan_karl_books_qs] == ["1"]
        assert susan_karl_books_qs.count() == 1

        # $Where
        custom_qs = Book.objects.filter(
            __raw__={
                "$where": """
                                            function(){
                                                return this.name == '1' ||
                                                       this.name == '2';}"""
            }
        )
        assert [str(b) for b in custom_qs] == ["1", "2"]

        # count only will work with this raw query before pymongo 4.x, but
        # the length is also implicitly checked above
        if PYMONGO_VERSION < (4,):
            assert custom_qs.count() == 2

    def test_switch_db_instance(self):
        register_connection("testdb-1", "mongoenginetest2")

        class Group(Document):
            name = StringField()

        Group.drop_collection()
        with switch_db(Group, "testdb-1") as Group:
            Group.drop_collection()

        Group(name="hello - default").save()
        assert 1 == Group.objects.count()

        group = Group.objects.first()
        group.switch_db("testdb-1")
        group.name = "hello - testdb!"
        group.save()

        with switch_db(Group, "testdb-1") as Group:
            group = Group.objects.first()
            assert "hello - testdb!" == group.name

        group = Group.objects.first()
        assert "hello - default" == group.name

        # Slightly contrived now - perform an update
        # Only works as they have the same object_id
        group.switch_db("testdb-1")
        group.update(set__name="hello - update")

        with switch_db(Group, "testdb-1") as Group:
            group = Group.objects.first()
            assert "hello - update" == group.name
            Group.drop_collection()
            assert 0 == Group.objects.count()

        group = Group.objects.first()
        assert "hello - default" == group.name

        # Totally contrived now - perform a delete
        # Only works as they have the same object_id
        group.switch_db("testdb-1")
        group.delete()

        with switch_db(Group, "testdb-1") as Group:
            assert 0 == Group.objects.count()

        group = Group.objects.first()
        assert "hello - default" == group.name

    def test_load_undefined_fields(self):
        class User(Document):
            name = StringField()

        User.drop_collection()

        User._get_collection().insert_one(
            {"name": "John", "foo": "Bar", "data": [1, 2, 3]}
        )

        with pytest.raises(FieldDoesNotExist):
            User.objects.first()

    def test_load_undefined_fields_with_strict_false(self):
        class User(Document):
            name = StringField()

            meta = {"strict": False}

        User.drop_collection()

        User._get_collection().insert_one(
            {"name": "John", "foo": "Bar", "data": [1, 2, 3]}
        )

        user = User.objects.first()
        assert user.name == "John"
        assert not hasattr(user, "foo")
        assert user._data["foo"] == "Bar"
        assert not hasattr(user, "data")
        assert user._data["data"] == [1, 2, 3]

    def test_load_undefined_fields_on_embedded_document(self):
        class Thing(EmbeddedDocument):
            name = StringField()

        class User(Document):
            name = StringField()
            thing = EmbeddedDocumentField(Thing)

        User.drop_collection()

        User._get_collection().insert_one(
            {
                "name": "John",
                "thing": {"name": "My thing", "foo": "Bar", "data": [1, 2, 3]},
            }
        )

        with pytest.raises(FieldDoesNotExist):
            User.objects.first()

    def test_load_undefined_fields_on_embedded_document_with_strict_false_on_doc(self):
        class Thing(EmbeddedDocument):
            name = StringField()

        class User(Document):
            name = StringField()
            thing = EmbeddedDocumentField(Thing)

            meta = {"strict": False}

        User.drop_collection()

        User._get_collection().insert_one(
            {
                "name": "John",
                "thing": {"name": "My thing", "foo": "Bar", "data": [1, 2, 3]},
            }
        )

        with pytest.raises(FieldDoesNotExist):
            User.objects.first()

    def test_load_undefined_fields_on_embedded_document_with_strict_false(self):
        class Thing(EmbeddedDocument):
            name = StringField()

            meta = {"strict": False}

        class User(Document):
            name = StringField()
            thing = EmbeddedDocumentField(Thing)

        User.drop_collection()

        User._get_collection().insert_one(
            {
                "name": "John",
                "thing": {"name": "My thing", "foo": "Bar", "data": [1, 2, 3]},
            }
        )

        user = User.objects.first()
        assert user.name == "John"
        assert user.thing.name == "My thing"
        assert not hasattr(user.thing, "foo")
        assert user.thing._data["foo"] == "Bar"
        assert not hasattr(user.thing, "data")
        assert user.thing._data["data"] == [1, 2, 3]

    def test_spaces_in_keys(self):
        class Embedded(DynamicEmbeddedDocument):
            pass

        class Doc(DynamicDocument):
            pass

        Doc.drop_collection()
        doc = Doc()
        setattr(doc, "hello world", 1)
        doc.save()

        one = Doc.objects.filter(**{"hello world": 1}).count()
        assert 1 == one

    def test_shard_key(self):
        class LogEntry(Document):
            machine = StringField()
            log = StringField()

            meta = {"shard_key": ("machine",)}

        LogEntry.drop_collection()

        log = LogEntry()
        log.machine = "Localhost"
        log.save()

        assert log.id is not None

        log.log = "Saving"
        log.save()

        # try to change the shard key
        with pytest.raises(OperationError):
            log.machine = "127.0.0.1"

    def test_shard_key_in_embedded_document(self):
        class Foo(EmbeddedDocument):
            foo = StringField()

        class Bar(Document):
            meta = {"shard_key": ("foo.foo",)}
            foo = EmbeddedDocumentField(Foo)
            bar = StringField()

        foo_doc = Foo(foo="hello")
        bar_doc = Bar(foo=foo_doc, bar="world")
        bar_doc.save()

        assert bar_doc.id is not None

        bar_doc.bar = "baz"
        bar_doc.save()

        # try to change the shard key
        with pytest.raises(OperationError):
            bar_doc.foo.foo = "something"
            bar_doc.save()

    def test_shard_key_primary(self):
        class LogEntry(Document):
            machine = StringField(primary_key=True)
            log = StringField()

            meta = {"shard_key": ("machine",)}

        LogEntry.drop_collection()

        log = LogEntry()
        log.machine = "Localhost"
        log.save()

        assert log.id is not None

        log.log = "Saving"
        log.save()

        # try to change the shard key
        with pytest.raises(OperationError):
            log.machine = "127.0.0.1"

    def test_kwargs_simple(self):
        class Embedded(EmbeddedDocument):
            name = StringField()

        class Doc(Document):
            doc_name = StringField()
            doc = EmbeddedDocumentField(Embedded)

            def __eq__(self, other):
                return self.doc_name == other.doc_name and self.doc == other.doc

        classic_doc = Doc(doc_name="my doc", doc=Embedded(name="embedded doc"))
        dict_doc = Doc(**{"doc_name": "my doc", "doc": {"name": "embedded doc"}})

        assert classic_doc == dict_doc
        assert classic_doc._data == dict_doc._data

    def test_kwargs_complex(self):
        class Embedded(EmbeddedDocument):
            name = StringField()

        class Doc(Document):
            doc_name = StringField()
            docs = ListField(EmbeddedDocumentField(Embedded))

            def __eq__(self, other):
                return self.doc_name == other.doc_name and self.docs == other.docs

        classic_doc = Doc(
            doc_name="my doc",
            docs=[Embedded(name="embedded doc1"), Embedded(name="embedded doc2")],
        )
        dict_doc = Doc(
            **{
                "doc_name": "my doc",
                "docs": [{"name": "embedded doc1"}, {"name": "embedded doc2"}],
            }
        )

        assert classic_doc == dict_doc
        assert classic_doc._data == dict_doc._data

    def test_positional_creation(self):
        """Document cannot be instantiated using positional arguments."""
        with pytest.raises(TypeError) as exc_info:
            self.Person("Test User", 42)

        expected_msg = (
            "Instantiating a document with positional arguments is not "
            "supported. Please use `field_name=value` keyword arguments."
        )
        assert str(exc_info.value) == expected_msg

    def test_mixed_creation(self):
        """Document cannot be instantiated using mixed arguments."""
        with pytest.raises(TypeError) as exc_info:
            self.Person("Test User", age=42)

        expected_msg = (
            "Instantiating a document with positional arguments is not "
            "supported. Please use `field_name=value` keyword arguments."
        )
        assert str(exc_info.value) == expected_msg

    def test_positional_creation_embedded(self):
        """Embedded document cannot be created using positional arguments."""
        with pytest.raises(TypeError) as exc_info:
            self.Job("Test Job", 4)

        expected_msg = (
            "Instantiating a document with positional arguments is not "
            "supported. Please use `field_name=value` keyword arguments."
        )
        assert str(exc_info.value) == expected_msg

    def test_mixed_creation_embedded(self):
        """Embedded document cannot be created using mixed arguments."""
        with pytest.raises(TypeError) as exc_info:
            self.Job("Test Job", years=4)

        expected_msg = (
            "Instantiating a document with positional arguments is not "
            "supported. Please use `field_name=value` keyword arguments."
        )
        assert str(exc_info.value) == expected_msg

    def test_data_contains_id_field(self):
        """Ensure that asking for _data returns 'id'."""

        class Person(Document):
            name = StringField()

        Person.drop_collection()
        Person(name="Harry Potter").save()

        person = Person.objects.first()
        assert "id" in person._data.keys()
        assert person._data.get("id") == person.id

    def test_complex_nesting_document_and_embedded_document(self):
        class Macro(EmbeddedDocument):
            value = DynamicField(default="UNDEFINED")

        class Parameter(EmbeddedDocument):
            macros = MapField(EmbeddedDocumentField(Macro))

            def expand(self):
                self.macros["test"] = Macro()

        class Node(Document):
            parameters = MapField(EmbeddedDocumentField(Parameter))

            def expand(self):
                self.flattened_parameter = {}
                for parameter_name, parameter in self.parameters.items():
                    parameter.expand()

        class NodesSystem(Document):
            name = StringField(required=True)
            nodes = MapField(ReferenceField(Node, dbref=False))

            def save(self, *args, **kwargs):
                for node_name, node in self.nodes.items():
                    node.expand()
                    node.save(*args, **kwargs)
                super().save(*args, **kwargs)

        NodesSystem.drop_collection()
        Node.drop_collection()

        system = NodesSystem(name="system")
        system.nodes["node"] = Node()
        system.save()
        system.nodes["node"].parameters["param"] = Parameter()
        system.save()

        system = NodesSystem.objects.first()
        assert (
            "UNDEFINED" == system.nodes["node"].parameters["param"].macros["test"].value
        )

    def test_embedded_document_equality(self):
        class Test(Document):
            field = StringField(required=True)

        class Embedded(EmbeddedDocument):
            ref = ReferenceField(Test)

        Test.drop_collection()
        test = Test(field="123").save()  # has id

        e = Embedded(ref=test)
        f1 = Embedded._from_son(e.to_mongo())
        f2 = Embedded._from_son(e.to_mongo())

        assert f1 == f2
        f1.ref  # Dereferences lazily
        assert f1 == f2

    def test_embedded_document_equality_with_lazy_ref(self):
        class Job(EmbeddedDocument):
            boss = LazyReferenceField("Person")
            boss_dbref = LazyReferenceField("Person", dbref=True)

        class Person(Document):
            job = EmbeddedDocumentField(Job)

        Person.drop_collection()

        boss = Person()
        worker = Person(job=Job(boss=boss, boss_dbref=boss))
        boss.save()
        worker.save()

        worker1 = Person.objects.get(id=worker.id)

        # worker1.job should be equal to the job used originally to create the
        # document.
        assert worker1.job == worker.job

        # worker1.job should be equal to a newly created Job EmbeddedDocument
        # using either the Boss object or his ID.
        assert worker1.job == Job(boss=boss, boss_dbref=boss)
        assert worker1.job == Job(boss=boss.id, boss_dbref=boss.id)

        # The above equalities should also hold after worker1.job.boss has been
        # fetch()ed.
        worker1.job.boss.fetch()
        assert worker1.job == worker.job
        assert worker1.job == Job(boss=boss, boss_dbref=boss)
        assert worker1.job == Job(boss=boss.id, boss_dbref=boss.id)

    def test_dbref_equality(self):
        class Test2(Document):
            name = StringField()

        class Test3(Document):
            name = StringField()

        class Test(Document):
            name = StringField()
            test2 = ReferenceField("Test2")
            test3 = ReferenceField("Test3")

        Test.drop_collection()
        Test2.drop_collection()
        Test3.drop_collection()

        t2 = Test2(name="a")
        t2.save()

        t3 = Test3(name="x")
        t3.id = t2.id
        t3.save()

        t = Test(name="b", test2=t2, test3=t3)

        f = Test._from_son(t.to_mongo())

        dbref2 = f._data["test2"]
        obj2 = f.test2
        assert isinstance(dbref2, DBRef)
        assert isinstance(obj2, Test2)
        assert obj2.id == dbref2.id
        assert obj2 == dbref2
        assert dbref2 == obj2

        dbref3 = f._data["test3"]
        obj3 = f.test3
        assert isinstance(dbref3, DBRef)
        assert isinstance(obj3, Test3)
        assert obj3.id == dbref3.id
        assert obj3 == dbref3
        assert dbref3 == obj3

        assert obj2.id == obj3.id
        assert dbref2.id == dbref3.id
        assert dbref2 != dbref3
        assert dbref3 != dbref2
        assert dbref2 != dbref3
        assert dbref3 != dbref2

        assert obj2 != dbref3
        assert dbref3 != obj2
        assert obj2 != dbref3
        assert dbref3 != obj2

        assert obj3 != dbref2
        assert dbref2 != obj3
        assert obj3 != dbref2
        assert dbref2 != obj3

    def test_default_values_dont_get_override_upon_save_when_only_is_used(self):
        class Person(Document):
            created_on = DateTimeField(default=lambda: datetime.utcnow())
            name = StringField()

        p = Person(name="alon")
        p.save()
        orig_created_on = Person.objects().only("created_on")[0].created_on

        p2 = Person.objects().only("name")[0]
        p2.name = "alon2"
        p2.save()
        p3 = Person.objects().only("created_on")[0]
        assert orig_created_on == p3.created_on

        class Person(Document):
            created_on = DateTimeField(default=lambda: datetime.utcnow())
            name = StringField()
            height = IntField(default=189)

        p4 = Person.objects()[0]
        p4.save()
        assert p4.height == 189

        # However the default will not be fixed in DB
        assert Person.objects(height=189).count() == 0

        # alter DB for the new default
        coll = Person._get_collection()
        for person in Person.objects.as_pymongo():
            if "height" not in person:
                coll.update_one({"_id": person["_id"]}, {"$set": {"height": 189}})

        assert Person.objects(height=189).count() == 1

    def test_shard_key_mutability_after_from_json(self):
        """Ensure that a document ID can be modified after from_json.

        If you instantiate a document by using from_json/_from_son and you
        indicate that this should be considered a new document (vs a doc that
        already exists in the database), then you should be able to modify
        fields that are part of its shard key (note that this is not permitted
        on docs that are already persisted).

        See https://github.com/mongoengine/mongoengine/issues/771 for details.
        """

        class Person(Document):
            name = StringField()
            age = IntField()
            meta = {"shard_key": ("id", "name")}

        p = Person.from_json('{"name": "name", "age": 27}', created=True)
        assert p._created is True
        p.name = "new name"
        p.id = "12345"
        assert p.name == "new name"
        assert p.id == "12345"

    def test_shard_key_mutability_after_from_son(self):
        """Ensure that a document ID can be modified after _from_son.

        See `test_shard_key_mutability_after_from_json` above for more details.
        """

        class Person(Document):
            name = StringField()
            age = IntField()
            meta = {"shard_key": ("id", "name")}

        p = Person._from_son({"name": "name", "age": 27}, created=True)
        assert p._created is True
        p.name = "new name"
        p.id = "12345"
        assert p.name == "new name"
        assert p.id == "12345"

    def test_from_json_created_false_without_an_id(self):
        class Person(Document):
            name = StringField()

        Person.objects.delete()

        p = Person.from_json('{"name": "name"}', created=False)
        assert p._created is False
        assert p.id is None

        # Make sure the document is subsequently persisted correctly.
        p.save()
        assert p.id is not None
        saved_p = Person.objects.get(id=p.id)
        assert saved_p.name == "name"

    def test_from_json_created_false_with_an_id(self):
        """See https://github.com/mongoengine/mongoengine/issues/1854"""

        class Person(Document):
            name = StringField()

        Person.objects.delete()

        p = Person.from_json(
            '{"_id": "5b85a8b04ec5dc2da388296e", "name": "name"}', created=False
        )
        assert p._created is False
        assert p._changed_fields == []
        assert p.name == "name"
        assert p.id == ObjectId("5b85a8b04ec5dc2da388296e")
        p.save()

        with pytest.raises(DoesNotExist):
            # Since the object is considered as already persisted (thanks to
            # `created=False` and an existing ID), and we haven't changed any
            # fields (i.e. `_changed_fields` is empty), the document is
            # considered unchanged and hence the `save()` call above did
            # nothing.
            Person.objects.get(id=p.id)

        assert not p._created
        p.name = "a new name"
        assert p._changed_fields == ["name"]
        p.save()
        saved_p = Person.objects.get(id=p.id)
        assert saved_p.name == p.name

    def test_from_json_created_true_with_an_id(self):
        class Person(Document):
            name = StringField()

        Person.objects.delete()

        p = Person.from_json(
            '{"_id": "5b85a8b04ec5dc2da388296e", "name": "name"}', created=True
        )
        assert p._created
        assert p._changed_fields == []
        assert p.name == "name"
        assert p.id == ObjectId("5b85a8b04ec5dc2da388296e")
        p.save()

        saved_p = Person.objects.get(id=p.id)
        assert saved_p == p
        assert saved_p.name == "name"

    def test_null_field(self):
        # 734
        class User(Document):
            name = StringField()
            height = IntField(default=184, null=True)
            str_fld = StringField(null=True)
            int_fld = IntField(null=True)
            flt_fld = FloatField(null=True)
            dt_fld = DateTimeField(null=True)
            cdt_fld = ComplexDateTimeField(null=True)

        User.objects.delete()
        u = User(name="user").save()
        u_from_db = User.objects.get(name="user")
        u_from_db.height = None
        u_from_db.save()
        assert u_from_db.height is None
        # 864
        assert u_from_db.str_fld is None
        assert u_from_db.int_fld is None
        assert u_from_db.flt_fld is None
        assert u_from_db.dt_fld is None
        assert u_from_db.cdt_fld is None

        # 735
        User.objects.delete()
        u = User(name="user")
        u.save()
        User.objects(name="user").update_one(set__height=None, upsert=True)
        u_from_db = User.objects.get(name="user")
        assert u_from_db.height is None

    def test_not_saved_eq(self):
        """Ensure we can compare documents not saved."""

        class Person(Document):
            pass

        p = Person()
        p1 = Person()
        assert p != p1
        assert p == p

    def test_list_iter(self):
        # 914
        class B(EmbeddedDocument):
            v = StringField()

        class A(Document):
            array = ListField(EmbeddedDocumentField(B))

        A.objects.delete()
        A(array=[B(v="1"), B(v="2"), B(v="3")]).save()
        a = A.objects.get()
        assert a.array._instance == a
        for idx, b in enumerate(a.array):
            assert b._instance == a
        assert idx == 2

    def test_updating_listfield_manipulate_list(self):
        class Company(Document):
            name = StringField()
            employees = ListField(field=DictField())

        Company.drop_collection()

        comp = Company(name="BigBank", employees=[{"name": "John"}])
        comp.save()
        comp.employees.append({"name": "Bill"})
        comp.save()

        stored_comp = get_as_pymongo(comp)
        self.assertEqual(
            stored_comp,
            {
                "_id": comp.id,
                "employees": [{"name": "John"}, {"name": "Bill"}],
                "name": "BigBank",
            },
        )

        comp = comp.reload()
        comp.employees[0]["color"] = "red"
        comp.employees[-1]["color"] = "blue"
        comp.employees[-1].update({"size": "xl"})
        comp.save()

        assert len(comp.employees) == 2
        assert comp.employees[0] == {"name": "John", "color": "red"}
        assert comp.employees[1] == {"name": "Bill", "size": "xl", "color": "blue"}

        stored_comp = get_as_pymongo(comp)
        self.assertEqual(
            stored_comp,
            {
                "_id": comp.id,
                "employees": [
                    {"name": "John", "color": "red"},
                    {"size": "xl", "color": "blue", "name": "Bill"},
                ],
                "name": "BigBank",
            },
        )

    def test_falsey_pk(self):
        """Ensure that we can create and update a document with Falsey PK."""

        class Person(Document):
            age = IntField(primary_key=True)
            height = FloatField()

        person = Person()
        person.age = 0
        person.height = 1.89
        person.save()

        person.update(set__height=2.0)

    def test_push_with_position(self):
        """Ensure that push with position works properly for an instance."""

        class BlogPost(Document):
            slug = StringField()
            tags = ListField(StringField())

        blog = BlogPost()
        blog.slug = "ABC"
        blog.tags = ["python"]
        blog.save()

        blog.update(push__tags__0=["mongodb", "code"])
        blog.reload()
        assert blog.tags == ["mongodb", "code", "python"]

    def test_push_nested_list(self):
        """Ensure that push update works in nested list"""

        class BlogPost(Document):
            slug = StringField()
            tags = ListField()

        blog = BlogPost(slug="test").save()
        blog.update(push__tags=["value1", 123])
        blog.reload()
        assert blog.tags == [["value1", 123]]

    def test_accessing_objects_with_indexes_error(self):
        insert_result = self.db.company.insert_many(
            [{"name": "Foo"}, {"name": "Foo"}]
        )  # Force 2 doc with same name
        REF_OID = insert_result.inserted_ids[0]
        self.db.user.insert_one({"company": REF_OID})  # Force 2 doc with same name

        class Company(Document):
            name = StringField(unique=True)

        class User(Document):
            company = ReferenceField(Company)

        # Ensure index creation exception aren't swallowed (#1688)
        with pytest.raises(DuplicateKeyError):
            User.objects().select_related()

    def test_embedded_document_failed_while_loading_instance_when_it_is_not_a_dict(
        self,
    ):
        class LightSaber(EmbeddedDocument):
            color = StringField()

        class Jedi(Document):
            light_saber = EmbeddedDocumentField(LightSaber)

        coll = Jedi._get_collection()
        Jedi(light_saber=LightSaber(color="red")).save()
        _ = list(Jedi.objects)  # Ensure a proper document loads without errors

        # Forces a document with a wrong shape (may occur in case of migration)
        value = "I_should_be_a_dict"
        coll.insert_one({"light_saber": value})

        with pytest.raises(InvalidDocumentError) as exc_info:
            list(Jedi.objects)

        assert str(
            exc_info.value
        ) == "Invalid data to create a `Jedi` instance.\nField 'light_saber' - The source SON object needs to be of type 'dict' but a '%s' was found" % type(
            value
        )


class ObjectKeyTestCase(MongoDBTestCase):
    def test_object_key_simple_document(self):
        class Book(Document):
            title = StringField()

        book = Book(title="Whatever")
        assert book._object_key == {"pk": None}

        book.pk = ObjectId()
        assert book._object_key == {"pk": book.pk}

    def test_object_key_with_custom_primary_key(self):
        class Book(Document):
            isbn = StringField(primary_key=True)
            title = StringField()

        book = Book(title="Sapiens")
        assert book._object_key == {"pk": None}

        book = Book(pk="0062316117")
        assert book._object_key == {"pk": "0062316117"}

    def test_object_key_in_a_sharded_collection(self):
        class Book(Document):
            title = StringField()
            meta = {"shard_key": ("pk", "title")}

        book = Book()
        assert book._object_key == {"pk": None, "title": None}
        book = Book(pk=ObjectId(), title="Sapiens")
        assert book._object_key == {"pk": book.pk, "title": "Sapiens"}

    def test_object_key_with_custom_db_field(self):
        class Book(Document):
            author = StringField(db_field="creator")
            meta = {"shard_key": ("pk", "author")}

        book = Book(pk=ObjectId(), author="Author")
        assert book._object_key == {"pk": book.pk, "author": "Author"}

    def test_object_key_with_nested_shard_key(self):
        class Author(EmbeddedDocument):
            name = StringField()

        class Book(Document):
            author = EmbeddedDocumentField(Author)
            meta = {"shard_key": ("pk", "author.name")}

        book = Book(pk=ObjectId(), author=Author(name="Author"))
        assert book._object_key == {"pk": book.pk, "author__name": "Author"}


class DBFieldMappingTest(MongoDBTestCase):
    def setUp(self):
        class Fields:
            w1 = BooleanField(db_field="w2")

            x1 = BooleanField(db_field="x2")
            x2 = BooleanField(db_field="x3")

            y1 = BooleanField(db_field="y0")
            y2 = BooleanField(db_field="y1")

            z1 = BooleanField(db_field="z2")
            z2 = BooleanField(db_field="z1")

        class Doc(Fields, Document):
            pass

        class DynDoc(Fields, DynamicDocument):
            pass

        self.Doc = Doc
        self.DynDoc = DynDoc

    def tearDown(self):
        for collection in list_collection_names(self.db):
            self.db.drop_collection(collection)

    def test_setting_fields_in_constructor_of_strict_doc_uses_model_names(self):
        doc = self.Doc(z1=True, z2=False)
        assert doc.z1 is True
        assert doc.z2 is False

    def test_setting_fields_in_constructor_of_dyn_doc_uses_model_names(self):
        doc = self.DynDoc(z1=True, z2=False)
        assert doc.z1 is True
        assert doc.z2 is False

    def test_setting_unknown_field_in_constructor_of_dyn_doc_does_not_overwrite_model_fields(
        self,
    ):
        doc = self.DynDoc(w2=True)
        assert doc.w1 is None
        assert doc.w2 is True

    def test_unknown_fields_of_strict_doc_do_not_overwrite_dbfields_1(self):
        doc = self.Doc()
        doc.w2 = True
        doc.x3 = True
        doc.y0 = True
        doc.save()
        reloaded = self.Doc.objects.get(id=doc.id)
        assert reloaded.w1 is None
        assert reloaded.x1 is None
        assert reloaded.x2 is None
        assert reloaded.y1 is None
        assert reloaded.y2 is None

    def test_dbfields_are_loaded_to_the_right_modelfield_for_strict_doc_2(self):
        doc = self.Doc()
        doc.x2 = True
        doc.y2 = True
        doc.z2 = True
        doc.save()
        reloaded = self.Doc.objects.get(id=doc.id)
        assert (
            reloaded.x1,
            reloaded.x2,
            reloaded.y1,
            reloaded.y2,
            reloaded.z1,
            reloaded.z2,
        ) == (doc.x1, doc.x2, doc.y1, doc.y2, doc.z1, doc.z2)

    def test_dbfields_are_loaded_to_the_right_modelfield_for_dyn_doc_2(self):
        doc = self.DynDoc()
        doc.x2 = True
        doc.y2 = True
        doc.z2 = True
        doc.save()
        reloaded = self.DynDoc.objects.get(id=doc.id)
        assert (
            reloaded.x1,
            reloaded.x2,
            reloaded.y1,
            reloaded.y2,
            reloaded.z1,
            reloaded.z2,
        ) == (doc.x1, doc.x2, doc.y1, doc.y2, doc.z1, doc.z2)


if __name__ == "__main__":
    unittest.main()