How to mock mongodb for python unittests?

Question

I am using mock module for Python 2.7 to mock my other functions and using

unittest for writing unit tests.

I am wondering if mocking the MongoDB is different than using mock functionality (mock.patch a function that is being called?) Or I need to use another different package for that purpose?

I do not think I want to have a test mongodb instance running. All I want is some tempo data and being able to call pymongo functionality. I am just a bit lost in thinking of is there a way to write a mock for a module (like pymongo), or anything is achievable by mock module.

So appreciate if you could provide an example or tutorial on this.

Code to Test

from pymongo import MongoClient  monog_url = 'mongodb://localhost:27017' client = MongoClient(monog_url) db = client.db  class Dao(object):    def __init__(self):       pass     def save(self, user):       db_doc = {         'name': user.name,         'email': user.email       }       db.users.save(db_doc)     def getbyname(self, user):       db_doc = {         'name': user.name,       }       return db.users.find(db_doc) 

To test this, I do not really want a test mongodb up and running! But also, I think I do not want to mock db.userssave and db.users.find because I want to actually be able to retrieve the data that I saved and make sure it is in the db. I think I need to create some fixtures per models that are in my memory and work with them. Just do I need an external tool to do so?

I am thinking of keeping some fake data like this, just do not know how to properly deal with it.

users = {      {'name' : 'Kelly', 'email' : '[email protected]'},     {'name': 'Sam', 'email': '[email protected]'} } 

Answer 1

I recommend using mongomock for mocking mongodb. It's basically an in-memory mongodb with pymongo interface and made specifically for this purpose.

https://github.com/mongomock/mongomock

Answer 2

You can also do this if you're just doing something simple, and you don't really need to retrieve by field.

@mock.patch("pymongo.collection.Collection.find") def test_name(self, mock_find):     mock_find.return_value = {'name' : 'Kelly', 'email' : '[email protected]'}     # rest of test