SQLAlchemy：没有这样的表，即使它们是实际创建的

Question

我开始用TDD开发一个烧瓶应用程序。在

生产代码和测试都在使用SQlite的同一个通用SQLAlchemy实例，以获得可重用性的好处。在

在初始py中：

db = SQLAlchemy()

因此，测试和实际应用程序都需要访问这个db实例，但需要使用不同的配置：测试.py使用/tmp/文件创建虚拟数据。在

因此，每次我使用'db'时，我都会注意调用正确的应用程序上下文，关于Flask_SQLAlchemy文档。在

结构：

^{pr2}$

以下是一些关键代码：

__初始py__：

from flask import Flask
from flask_sqlalchemy import SQLAlchemy

db = SQLAlchemy()

from application.models import *

def create_app(conf_object):
    app = Flask(__name__)
    app.config.from_object(conf_object)
    db.init_app(app)
    return (app, db)

测试.py：

from flask_sqlalchemy import SQLAlchemy
from application import create_app
import unittest
import os


app, db = create_app('application.config.TestConf') # Test conf: db file will bt a tempfile
from application.models import Update, Update_State, Device, Confirmation
db.create_all(app=app) # Create tables with app context


class APITestCase(unittest.TestCase):

    def setUp(self):
        """Sets up a hardcoded dummy-data database before each test"""

        # Hardcoded fake database

        d1 = Device('1223456789', 'hub', 'R3pTkEAHyUKbUJW7bSK8k5')
        d2 = Device('AZERTY', 'hub', 'R3pTkEAHyUKbUJW7bSK8k5')

        db.session.add(d1)
        db.session.add(d2)

        db.session.commit()

        self.app = app.test_client()

    def tearDown(self):
        """Destroy fake db after each test"""
        os.close(app.config['DB_FD'])
        os.unlink(app.config['DB_FILE'])


    # assert functions

    def test_confirmation_msg_correct(self):
        tester = app.test_client(self)
        response = tester.get('/confirmation-msg', query_string=dict(deviceid='1223456789', updateid='R3pTkEAHyUKbUJW7bSK8k5'), content_type='html/text')
        self.assertEqual(response.status_code, 200)



if __name__ == '__main__':
    with app.app_context(): # Because using using a generic SQLAlchemy() 'db' instance, we need to specify the app. See Flask_sqlalchemy doc, 'Introduction into contexts'
        unittest.main()

模型.py：

from application import db
import datetime
import shortuuid

class Device(db.Model):
    id = db.Column(db.String(255), primary_key=True)
    type = db.Column(db.String(255))
    version_id = db.Column(db.String(511))

    def __init__(self, id, type, version_id):
        self.id = id
        self.type = type
        self.version_id = version_id

还有一些其他的模型，但为了解释，我尽量简单。在

问题出在setUp（self）函数中，其中虚拟数据被添加到数据库中。即使模型已导入并且代码在正确的应用程序上下文中执行，引擎也找不到表。在

无此类表格：设备

sqlalchemy.exc.InvalidRequestError: This Session's transaction has been rolled back due to a previous exception during flush. To begin a new transaction with this Session, first issue Session.rollback(). Original exception was: (sqlite3.OperationalError) no such table: device [SQL: 'INSERT INTO device (id, type, version_id) VALUES (?, ?, ?)'] [parameters: (('1223456789', 'hub', 'R3pTkEAHyUKbUJW7bSK8k5'), ('AZERTY', 'hub', 'R3pTkEAHyUKbUJW7bSK8k5'))] (Background on this error at: http://sqlalche.me/e/e3q8)

此外，这些表显然是用全部创建数据库（app=app），当设置SQLALCHEMY_ECHO=True时：

2018-07-31 17:06:45,333 INFO sqlalchemy.engine.base.Engine SELECT CAST('test plain returns' AS VARCHAR(60)) AS anon_1
2018-07-31 17:06:45,333 INFO sqlalchemy.engine.base.Engine ()
2018-07-31 17:06:45,334 INFO sqlalchemy.engine.base.Engine SELECT CAST('test unicode returns' AS VARCHAR(60)) AS anon_1
2018-07-31 17:06:45,334 INFO sqlalchemy.engine.base.Engine ()
2018-07-31 17:06:45,334 INFO sqlalchemy.engine.base.Engine PRAGMA table_info("update__state")
2018-07-31 17:06:45,334 INFO sqlalchemy.engine.base.Engine ()
2018-07-31 17:06:45,335 INFO sqlalchemy.engine.base.Engine PRAGMA table_info("device")
2018-07-31 17:06:45,335 INFO sqlalchemy.engine.base.Engine ()
2018-07-31 17:06:45,335 INFO sqlalchemy.engine.base.Engine PRAGMA table_info("confirmation")
2018-07-31 17:06:45,335 INFO sqlalchemy.engine.base.Engine ()
2018-07-31 17:06:45,335 INFO sqlalchemy.engine.base.Engine PRAGMA table_info("update")
2018-07-31 17:06:45,336 INFO sqlalchemy.engine.base.Engine ()
2018-07-31 17:06:45,336 INFO sqlalchemy.engine.base.Engine 
CREATE TABLE "update" (
    update_id VARCHAR(511) NOT NULL, 
    version VARCHAR(255), 
    description VARCHAR(2047), 
    date_created DATETIME, 
    PRIMARY KEY (update_id)
)


2018-07-31 17:06:45,336 INFO sqlalchemy.engine.base.Engine ()
2018-07-31 17:06:45,349 INFO sqlalchemy.engine.base.Engine COMMIT
2018-07-31 17:06:45,350 INFO sqlalchemy.engine.base.Engine 
CREATE TABLE update__state (
    last_communicated_version_id VARCHAR(255) NOT NULL, 
    PRIMARY KEY (last_communicated_version_id), 
    FOREIGN KEY(last_communicated_version_id) REFERENCES "update" (update_id)
)


2018-07-31 17:06:45,350 INFO sqlalchemy.engine.base.Engine ()
2018-07-31 17:06:45,368 INFO sqlalchemy.engine.base.Engine COMMIT
2018-07-31 17:06:45,376 INFO sqlalchemy.engine.base.Engine 
CREATE TABLE device (
    id VARCHAR(255) NOT NULL, 
    type VARCHAR(255), 
    version_id VARCHAR(511) NOT NULL, 
    PRIMARY KEY (id), 
    FOREIGN KEY(version_id) REFERENCES "update" (update_id)
)


2018-07-31 17:06:45,377 INFO sqlalchemy.engine.base.Engine ()
2018-07-31 17:06:45,387 INFO sqlalchemy.engine.base.Engine COMMIT
2018-07-31 17:06:45,388 INFO sqlalchemy.engine.base.Engine 
CREATE TABLE confirmation (
    id INTEGER NOT NULL, 
    device_id INTEGER, 
    version_id VARCHAR(511) NOT NULL, 
    timestamp DATETIME, 
    PRIMARY KEY (id), 
    UNIQUE (device_id), 
    FOREIGN KEY(device_id) REFERENCES device (id), 
    FOREIGN KEY(version_id) REFERENCES "update" (update_id)
)

希望我清楚，提前谢谢。在

Answer 1

已解决：

tmp无法在文件中写入/临时文件.mkstemp(). 使用相对本地路径，它可以工作。在