如何测试 function 是否引发 Flask 正确中止？

Question

I am trying to create unittests for my flask application which should assert exceptions properly.

I am attaching simplified code sample on what i want to test. The below test should finish as success.

def my_function():
    abort(400,"error")

import unittest

from werkzeug import exceptions

class Tests(unittest.TestCase):

    def test_event_link(self):
        self.assertRaises(exceptions.BadRequest,my_function)

unittest.main(argv=[''], verbosity=2, exit=False)

Answer 1

I would simply patch the Flask abort function and ensure it is called with the correct value, this is preferable as it only tests your code not the behaviour of Flasks abort function which could change with future versions of Flask and break your tests.

See below example based on your code which also includes examples of testing the exception if this is what you would prefer to do.

# code.py

from flask import abort


def my_function():
    abort(400, "error")

# test.py

import unittest
from unittest.mock import patch
from werkzeug import exceptions

import code  # Your code file code.py


class Tests(unittest.TestCase):

    @patch('code.abort')
    def test_one(self, mock_abort):
        code.my_function()
        mock_abort.assert_called_once_with(400, 'error')

    def test_two(self):
        with self.assertRaises(exceptions.BadRequest):
            code.my_function()

    def test_three(self):
        with self.assertRaisesRegexp(exceptions.BadRequest, '400 Bad Request: error'):
            code.my_function()


unittest.main(argv=[''], verbosity=2, exit=False)