Brtdku

I have some issues to mock a SQLAlchemy object when using the default and onupdate fields in my models :

def get_uuid():

    return str(uuid.uuid4())



def get_now():

    return db.func.now()



class BaseModel(db.Model):

    __abstract__ = True



    id = db.Column(UUIDType(binary=False), primary_key=True, nullable=False, default=get_uuid)

    created_at = db.Column(db.DateTime(timezone=True), default=get_now(), nullable=False, index=True)

The get_now() and get_uuid() behaviour do not change even when I try to mock them in my tests :

def test_create_source(client, mocker):



    mock = mocker.MagicMock(return_value='123e4567-e89b-12d3-a456-426655440000')

    mocker.patch('myproject.models.get_uuid', mock)

    mock = mocker.MagicMock(return_value=datetime.datetime(2019, 1, 1))

    mocker.patch('myproject.models.get_now', mock)



    resp = client.post('/sources', json={'name': 'My source'})

    assert resp.json == {

        'name': 'My source',

        'id': '123e4567-e89b-12d3-a456-426655440000',

        'createdAt': 'Tue, 01 Jan 2019 00:00:00 GMT',

        'updatedAt': 'Tue, 01 Jan 2019 00:00:00 GMT'

    }



### Results :



>       assert resp.json == {

            'name': 'My source',

            'id': '123e4567-e89b-12d3-a456-426655440000',

            'createdAt': 'Tue, 01 Jan 2019 00:00:00 GMT',

            'updatedAt': 'Tue, 01 Jan 2019 00:00:00 GMT'

        }

E       AssertionError: assert {'createdAt':...17:38:38 GMT'} == {'createdAt': ...00:00:00 GMT'}

E         Omitting 1 identical items, use -vv to show

E         Differing items:

E         {'id': '8eb074c0-41e9-436c-8f71-b4c6842f4809'} != {'id': '123e4567-e89b-12d3-a456-426655440000'}

E         {'createdAt': 'Fri, 18 Jan 2019 17:38:38 GMT'} != {'createdAt': 'Tue, 01 Jan 2019 00:00:00 GMT'}

E         {'updatedAt': 'Fri, 18 Jan 2019 17:38:38 GMT'} != {'updatedAt': 'Tue, 01 Jan 2019 00:00:00 GMT'}

E         Use -v to get the full diff



tests/test_sources.py:17: AssertionError

I think it's because my models and its attributes are already imported and evaluated before doing my test, so the mock is useless here. It's explained in the "Mocking class helpers" part of this post but I still was not able to fix my issue :(

The full runnable code to reproduce the problem is available here : https://github.com/ncrocfer/flaskmock

Do you have some ideas please ?

I think it's because my models and its attributes are already imported and evaluated before doing my test, so the mock is useless here.

Close: you've passed a reference to function get_uuid() as default to id and the result of calling get_now() (a function expression object) as default to created_at. Changing what those names are bound to in the module after the fact has no effect anymore on the columns, which already hold references to the objects themselves.

In case of get_uuid() you should mock the function it is calling:

mock = mocker.MagicMock(return_value='123e4567-e89b-12d3-a456-426655440000')

mocker.patch('uuid.uuid4', mock)

and in case of get_now() you should consider not calling it during model construction:

class BaseModel(db.Model):

    ...

    created_at = db.Column(..., default=get_now, ...)

so that you can again mock the actual function it is calling:

mock = mocker.MagicMock(return_value=datetime.datetime(2019, 1, 1))

mocker.patch('sqlalchemy.func.now', mock)

On the other hand perhaps you should not be asserting anything about id and the timestamps in the test, since it seems that the important thing is to verify that the name was set correctly.