Flask 应用程序无法为请求创建 URL 适配器

Question

我有这个曾经可以工作的代码：

import unittest

from flask import url_for

from dm.web import create_app, db


class TestApi(unittest.TestCase):
    def setUp(self):
        """Create and configure a new app instance for each test."""
        self.app = create_app('test')
        self.app_context = self.app.app_context()
        self.app_context.push()
        db.create_all()
        self.client = self.app.test_client(use_cookies=True)

    def tearDown(self) -> None:
        db.session.remove()
        db.drop_all()
        self.app_context.pop()

    def test_url(self):
        self.assertEqual('/', url_for('root.home'))

if __name__ == '__main__':
    unittest.main()

但是从今天开始我收到了这个错误：

ERROR: test_url (__main__.TestApi)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/joan/.PyCharmCE2019.3/config/scratches/scratch.py", line 17, in test_url
    self.assertEqual('/', url_for('root.home'))
  File "/home/joan/venvs/dimensigon3.7/lib/python3.7/site-packages/flask/helpers.py", line 333, in url_for
    "Application was not able to create a URL adapter for request"
RuntimeError: Application was not able to create a URL adapter for request independent URL generation. You might be able to fix this by setting the SERVER_NAME config variable.

根据我在 url_for 中看到的内容，我在 appctx.url_adapter 上得到 None ，我不知道它何时设置。

谢谢！

Answer 1

根据blog post，您可以尝试这种模式，它为您提供应用上下文和临时请求上下文：

    def test_url(self):
        with app.app_context(), app.test_request_context():
            self.assertEqual('/', url_for('root.home'))