from flask import Flask

def create_app(config_filename = None):
    app = Flask(__name__)
    if config_filename is None:
        app.config.from_pyfile('config.py', silent=True)
    else:
        app.config.from_mapping(config_filename)

    from .model import db
    db.init_app(app)
    db.create_all(app=app)

    return app

from flask_sqlalchemy import SQLAlchemy

db = SQLAlchemy()

class Document(db.Model):
    id = db.Column(db.Integer, primary_key=True)
    document_uri = db.Column(db.String, nullable=False, unique=True)

import pytest
from model import Document, db
from myapplication import create_app

@pytest.fixture
def app():
    config = {
        'SQLALCHEMY_DATABASE_URI': f"sqlite:///:memory:",
        'TESTING': True,
        'SQLALCHEMY_TRACK_MODIFICATIONS': False
    }
    app = create_app(config)
    yield app
    with app.app_context():
        db.drop_all()

@pytest.fixture
def app_with_documents(app):
    with app.app_context():
        document_1 = Document(document_uri='Document 1')
        document_2 = Document(document_uri='Document 2')
        document_3 = Document(document_uri='Document 3')
        document_4 = Document(document_uri='Document 4')
        db.session.add_all([document_1, document_2, document_3, document_4])
        db.session.commit()
    return app

def test_unit_test_1(app_with_documents):
    ...

def test_unit_test_2(app_with_documents):
    ...

def do_execute(self, cursor, statement, parameters, context=None):
>       cursor.execute(statement, parameters)
E       sqlalchemy.exc.OperationalError: (sqlite3.OperationalError) no such table: document [SQL: 'INSERT INTO document (document_uri) VALUES (?)'] [parameters: ('Document 1',)] (Background on this error at: http://sqlalche.me/e/e3q8)

@pytest.fixture
def app():
    """
    A Flask application.
    """
    db_fd, db_filename = tempfile.mkstemp(suffix='.sqlite')
    config = {
        'SQLALCHEMY_DATABASE_URI': f"sqlite:///{db_filename}",
        'TESTING': True,
        'SQLALCHEMY_TRACK_MODIFICATIONS': False
    }
    yield create_app(config)
    os.close(db_fd)
    os.unlink(db_filename)