Flask-sqlalchemy 3.0.2 creating a new DB inside a Flask endpoint - flask

Question

I'm currently migrating my Flask app from flask-sqlalchemy 2.5.1 to 3.0.2. The app includes an endpoint that lets the client create a new database file at a selected path. Before the migration, it was achieved by simply setting the path and creating the tables in the following way:
app.config['SQLALCHEMY_DATABASE_URI'] = filepath
db.create_all()
However, the file is no longer automatically created in 3.0.2.
Question
I have been digging through the flask-sqlalchemy and sqlalchemy documentations for the past two days yet I can't find anything that would mention the changed behaviour. Creating the file before setting the config doesn't work either, as the tables are not created and the file size is 0b after calling the endpoint.
How can I create a new sqlalchemy DB file inside of a Flask endpoint?
Below is a minimal reproducible example:
server.py
from flask import Flask
from flask_sqlalchemy import SQLAlchemy
import os
TEST_DB_PATH = os.path.join(os.getcwd(), "test.db")
# create the extension
db = SQLAlchemy()
class User(db.Model):
id = db.Column(db.Integer, primary_key=True)
# create the app
app = Flask(__name__)
app.config["SQLALCHEMY_TRACK_MODIFICATIONS"] = True
# configure the first SQLite database, in memory
app.config["SQLALCHEMY_DATABASE_URI"] = "sqlite:///"
# initialize the app with the extension
db.init_app(app)
with app.app_context():
db.create_all()
#app.route('/test')
def test():
# configure the second SQLite database, relative to the app instance folder
app.config["SQLALCHEMY_DATABASE_URI"] = "sqlite:///" + TEST_DB_PATH
db.create_all()
return "OK", 200
if __name__ == '__main__':
app.run()
test_server.py
import server
import os
import pytest
#pytest.fixture(scope="session")
def client():
app = server.app
return app.test_client()
def test_create_db_file(client):
# clean local test.db file if it exists
try:
os.remove(server.TEST_DB_PATH)
except OSError:
pass
ans = client.get("test")
assert ans.status_code == 200, ans.data
# this assertion fails
assert os.path.exists(
server.TEST_DB_PATH), f"DB file created at execution cannot be found at " + server.TEST_DB_PATH
assert os.path.getsize(
server.TEST_DB_PATH) > 0, "Created db file size is 0"
Running the test
py -m pytest .\test_server.py
The assertions fail with flask-sqlalchemy 3.0.2 and pass with 2.5.1.
Environment
Windows 11 x64
flask-sqlalchemy 2.2.2
sqlalchemy 1.4.46
pytest 7.2.0
python 3.9.13