DB not changing when testing Flask-Security with peewe and PyTest

Question

I just got into testing my flask application with pytest, and it mostly works as expected. Unfortunately the test uses the live DB instead a mock one. I'm quite sure this has to do with the fact, that flask-security is using peewee's database_wrapper instead of an "straightforward" database.

Here's some code. This is from the test:

@pytest.fixture
def client():
db_fd, belavoco_server.app.config['DATABASE']  = {  'name': 'userLogin_TEST.db',
                                                    'engine': 'peewee.SqliteDatabase' }                                                   }

belavoco_server.app.config['TESTING'] = True
client = belavoco_server.app.test_client()

#this seems not to help at all
with belavoco_server.app.app_context():
     belavoco_server.users.user_managment.db_wrapper.init_app(belavoco_server.app)

yield client

os.close(db_fd)
os.unlink(belavoco_server.app.config['DATABASE'])

This is some code from my bv_user_model.py

app.config['DATABASE'] = {
    'name': 'userLogin.db',
    'engine': 'peewee.SqliteDatabase',
}

app.config['SECURITY_URL_PREFIX'] = "/users"

# Create a database instance that will manage the connection and
# execute queries
db_wrapper = FlaskDB(app)

class Role(db_wrapper.Model, RoleMixin):
    name = CharField(unique=True, default="standard")
    description = TextField(null=True)

    def __repr__(self):
        return self.name

When preforming the test, Flask is using the userLogin.db instead of userLogin_TEST.db. I suppose this is because of the db_wrapper in bv_user_model.py - but I did not find a way to change this behaviour. Any help would be greatly appreciated!

Your example is not reproducible and that may be the reason why this question has not received enough attention. The fixture appears to be malformatted (no indent). And what is `belavoco_server`? Also, may I ask what is the purpose of unpacking the dictionary keys into `db_fd and belavoco_server.app.config['DATABASE']`? It does not make any sense to me as `db_df` would be a string, not a file descriptor. — krassowski, May 18 '19 at 08:58
You are right, the question was not well asked, but I really got lost with this problem, because the code itself worked and I am new to tests. `belavoco_server` is the name of the whole project, the app is created therein. You're right, the unpacking makes no sense, it comes from the code before, which was creating a temporary file with `tempfile.mkstemp()` which returns a pair. — leosok, May 21 '19 at 00:16
I did find a solution after all, using the same BaseModel and initializing the database with a temporary file as I did for other tests. Because the example of flask-security used a database wrapper I thought I had to use FlaskDB. Without it, everything works fine. — leosok, May 21 '19 at 00:16

score 1 · Accepted Answer · answered May 20 '19 at 20:52

The root of the issue seems to be this in bv_user_model:

app.config['DATABASE'] = {
    'name': 'userLogin.db',
    'engine': 'peewee.SqliteDatabase',
}

Since you are using FlaskDB with the app that has the production credentials, it seems like the db_wrapper will "remember" that and not be overridden by your tests.

The most straightforward answer would be to not use your app to create the FlaskDB instance directly

db = FlaskDB()

And then later on initialize it on your app

from models import db
def create_app():
    app = ...
    app.config["DATABASE"] = ...
    db.init_app(app)
    ...
    return app

Which would let you have a separate function like this which you can use for testing.

def create_test_app():
    app = ...
    app.config["DATABASE"] = ...test credentials...
    db.init_app(app)
    ...
    return app

and when you create your models, use the FlaskDB instance just the same as you were already.

db = FlaskDB()
class Role(db.Model, RoleMixin):
    ...

Thank you, you nailed the problem. I found a solution myself, in the meantime, by ditching FlaskDB and returning to a BaseModel and initiation with `database.init(database_name)` if `not app.config['TESTING']`. This is what worked for all the other tests, but (as I'm explaining in a comment above) I was thinking I had to use a db_wrapper to use flask-security. — leosok, May 21 '19 at 00:25
I have never opend and closed connections manually with peewee and Flask. Apparently FlaskDB does this for you. I have used Flask an peewee for a while and never had any problem with not closing connections, I was always assuming they were closed automatically. When using the Models obviously a connection is opend. Should I use a hook to close it when a request ends? — leosok, May 21 '19 at 00:34

DB not changing when testing Flask-Security with peewe and PyTest

1 Answers1