mongoengine connect() in settings.py testing problem

Question

I want to be able to do conditional connect() based on either I started django in testing mode or not.

in my settings.py I use mongoengine connect() method to connect to

Answer 1

What I do is use register_connection, and then mock the connections on test.

In the file that I define the Mongo Documents I have this:

import mongoengine
from django.conf import settings

mongoengine.register_connection(
    'default', settings.MONGOENGINE_DB, **settings.MONGOENGINE_CONNECTION)

Then in the tests I use the mock library to change the behave of connections (it would be possible too to mock one of the functions on the connection sub module like get_db) like this:

connections = patch.dict(
    mongoengine.connection._connections, {'default': None})

dbs = patch.dict(
    mongoengine.connection._dbs, {'default': {
        'your_collection': None,
        'another_collection': None,
        }})

dbs.start()
connections.start()

insert = patch.object(mongoengine.queryset.QuerySet, 'insert')
insert_mock = insert.start()

...

insert_mock.assert_called_once(...)

Answer 2

I'm solving this with a custom test runner. Here is an example I based my solution off of: https://github.com/xintron/django-mongorunner/blob/master/mongorunner/testrunner.py

This has the advantage of providing a fresh database for each of your unit tests.

class MyTestRunner(DjangoTestSuiteRunner):

    mongodb_name = 'testsuite'

    def setup_databases(self, **kwargs):
        from mongoengine.connection import connect, disconnect
        disconnect()
        connect(self.mongodb_name)
        print 'Creating mongo test-database ' + self.mongodb_name
        return super(MyTestRunner, self).setup_databases(**kwargs)

    def teardown_databases(self, old_config, **kwargs):
        from mongoengine.connection import get_connection, disconnect
        connection = get_connection()
        connection.drop_database(self.mongodb_name)
        print 'Dropping mongo test-database: ' + self.mongodb_name
        disconnect()
        super(MyTestRunner, self).teardown_databases(old_config, **kwargs)

Answer 3

I'm not sure it's completely foolproof, but I use the fact that in a test, you will have probably started it from the command line with ./manage.py test, so 'test' is one of the command-line args. So this works:

import sys
if 'test' not in sys.argv:
    mongodb.connect()

Answer 4

While it is possible to do that, it is easier and common practice to have 2 settings files. One possible configuration could be:

You have 2 settings files, lsettings.py that doesn't connect and settings.py that does

from lsettings import *
mongodb.connect()

So, while locally testing you can:

python manage.py test --settings=lsettings

And it doesn't connect.

tl;dr: It is easier to manage configuration differences by having multiple configuration files that import each other conditionally rather than trying to have conditional parameters within the same settings file. YMMV.