find_one() doesn't work with object ID

[SCSR-is-too-short-username]

I'm trying to write tests for functions that rely on using object IDs. These work fine when running normally, but while writing unit tests for the functions I noticed that using object IDs doesn't work when using mongomock.

Here is some code I have:

# test_versioning.py

import os

import mongomock
import pytest
from bson import ObjectId

import app.services.documentdb as doc_db


@pytest.fixture(autouse=True)
def clean_up(mocker):
    db = mongomock.MongoClient()
    mocker.patch("app.services.documentdb.get", return_value=db)

    database = db[os.environ["DOC_DB_NAME"]]
    coll_data = database[os.environ["DOC_DB_DATA_COLLECTION"]]
    coll_vh = database[os.environ["DOC_DB_VERSION_HISTORY_COLLECTION"]]

    coll_data.insert_one(
        {"_id": ObjectId("65780d19d8df6164d4f356ad"), "Instance": "Instance 1", "Name": "Name 1", "Type": "Type 2", "SerialNumber": "01234567"}
    )
    coll_vh.insert_one(
        {
            "revision_for": ObjectId("65780d19d8df6164d4f356ad"),
            "source_collection": "datacollection",
            "current_revision": 2,
            "revisions": [
                {
                    "revision": 1,
                    "updated_by": "test_person",
                    "update_time": "7-12-2023-12-30",
                    "changed_fields": {},
                    "added_fields": {"Instance": "Instance 1", "Name": "Name 1", "Type": "Type 1", "SerialNumber": "01234567"},
                },
                {
                    "revision": 2,
                    "updated_by": "test_person",
                    "update_time": "8-12-2023-12-30",
                    "changed_fields": {"Type": "Type 2"},
                    "added_fields": {},
                },
            ],
        }
    )

    mocker.patch("app.services.access.get_user_access", return_value=True)

    yield

    db.drop_database(os.environ["DOC_DB_NAME"])


def test_get_revision_history():
    response = doc_db.get_full_revision_doc("DOC_DB_DATA_COLLECTION", "65780d19d8df6164d4f356ad")

    assert response["source_collection"] == "datacollection"

# documentdb.py

def get_full_revision_doc(source_coll, doc_id):
    db = get()
    database = db[os.environ["DOC_DB_NAME"]]
    collection = database[os.environ["DOC_DB_VERSION_HISTORY_COLLECTION"]]

    return collection.find_one({"revision_for": ObjectId(doc_id), "source_collection": os.environ[source_coll]})

This is a very important feature for our project and we need robust unit tests for it to make sure everything works. With this issue present in mongomock, it is not possible. I hope you can get this fixed soon!

[warownia1]

I tried to isolate and reproduce the problem you described, but I couldn't. Here is the code I used in my test. I removed all pieces of code not relevant to the described issue. Tested on Python 3.12 and both mongomock 4.0.0 and 4.1.2

import mongomock
import pytest
from bson import ObjectId


DOC_DB_NAME = "mydatabasename"
DOC_DB_VERSION_HISTORY_COLLECTION = "mycollectionname"


@pytest.fixture
def database():
  db = mongomock.MongoClient()
  database = db[DOC_DB_NAME]
  yield database
  db.drop_database(database)


def test_get_revision_history(database):
  coll_vh = database[DOC_DB_VERSION_HISTORY_COLLECTION]
  coll_vh.insert_one(
    {
      "revision_for": ObjectId("65780d19d8df6164d4f356ad"),
      "source_collection": "datacollection",
      "current_revision": 2,
      # e.t.c
    }
  )
  item = coll_vh.find_one({"revision_for": ObjectId("65780d19d8df6164d4f356ad")})
  assert item is not None

The test passes, so it doesn't seem to be an issue with the mongomock. I suggest you check if the MongoClient object you set in a mock and one you access later are the same object. The way you set up the test and use global module to store and retrieve the client suggests me the problem could be with the mocking.