"RuntimeError: working outside of application context" when unit testing with py.test

Question

I'm trying to migrate to py.test for the ease of use and auto-discovery of tests. When I run my tests with unittest, the test works fine. When I run the test under py.test, I get RuntimeError: working outside of application context.

Here's the test code (test_app.py):

import unittest

from app import app

class TestAPILocally(unittest.TestCase):
    def setUp(self):
        self.client = app.test_client()

    def testRoot(self):
        retval = self.client.get('/').data
        self.assertTrue('v1' in retval)

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

And here's the stripped down file I'm testing (app.py):

from flask import Flask
from flask.ext.restful import Api, Resource

class APIListAPI(Resource):
    def get(self):
        return ['v1']

app = Flask(__name__)
api = Api(app)
api.add_resource(APIListAPI, '/')

As you can see, this is very similar to the docs on the flask site: the testing skeleton, and indeed, when I run it with unittest, it succeeds:

$ python tmp1/test_app.py 
.
----------------------------------------------------------------------
Ran 1 test in 0.115s

OK
$

But, when I test with py.test, it fails:

$ ./py.test tmp1/test_app.py
=================== test session starts =========================
platform sunos5 -- Python 2.7.5 -- py-1.4.22 -- pytest-2.6.0
collected 1 items

tmp1/test_app.py F

========================= FAILURES ==============================
_________________ TestAPILocally.testRoot _______________________

self = <tmp1.test_app.TestAPILocally testMethod=testRoot>

    def testRoot(self):
>       retval = self.client.get('/').data

tmp1/test_app.py:10:
 _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
werkzeug/test.py:762: in get
    return self.open(*args, **kw)
flask/testing.py:108: in open
    follow_redirects=follow_redirects)
werkzeug/test.py:736: in open
    response = self.run_wsgi_app(environ, buffered=buffered)
werkzeug/test.py:659: in run_wsgi_app
    rv = run_wsgi_app(self.application, environ, buffered=buffered)
werkzeug/test.py:855: in run_wsgi_app
    app_iter = app(environ, start_response)
tmp1/flask/app.py:1836: in __call__
    return self.wsgi_app(environ, start_response)
tmp1/flask/app.py:1820: in wsgi_app
    response = self.make_response(self.handle_exception(e))
flask_restful/__init__.py:256: in error_router
    if self._has_fr_route():
flask_restful/__init__.py:237: in _has_fr_route
    if self._should_use_fr_error_handler():
flask_restful/__init__.py:218: in _should_use_fr_error_handler
    adapter = current_app.create_url_adapter(request)
werkzeug/local.py:338: in __getattr__ 
    return getattr(self._get_current_object(), name)
werkzeug/local.py:297: in _get_current_object
    return self.__local()
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

    def _find_app():
        top = _app_ctx_stack.top
        if top is None:
>           raise RuntimeError('working outside of application context')
E           RuntimeError: working outside of application context

flask/globals.py:34: RuntimeError
================ 1 failed in 1.02 seconds ======================

Now, it turns out, I can make this test pass just by doing this:

$ rm tmp1/__init__.py

And make it fail again by doing this:

$ touch tmp1/__init__.py

So, is there some difference between the way that unittest and py.test handles files in modules? It seems very strange that it breaks enough to make Flask complain, as I clearly am in an app context calling app.test_client().get(). Is this expected behavior, or should I file a bug against py.test?

In case it's relevant, the reason I'm executing the tests from the parent directory is because I don't have the ability to add modules to site-packages, so I'm initiating all my code from the parent directory, where I've installed Flask, py.test, etc.

Edit: Solved. It was an installation problem. Adding pythonpath tag, since that was the solution.

Can't reproduce. Can you please add used versions, file structure, and command to run test? — tbicr, Jul 22 '14 at 06:17
@tbicr - Thanks. I looked into it further with a virtual machine, and it doesn't happen if I pip install flask. I'll put up an answer in a minute explaining what went wrong. — John Hazen, Jul 22 '14 at 17:18

MadisonTrash · Answer 1 · 2017-03-11T12:07:07.370

Not directly answer to TS question, but mostly for 'application context' error.

Adding pushing and poping context in setUp and tearDown functions should help with this error:

def setUp(self):
    self.app_context = app.app_context()
    self.app_context.push()

def tearDown(self):
    self.app_context.pop()

You can find more info on flask context there:

also in this awesome article by Daniel Kronovet:

http://kronosapiens.github.io/blog/2014/08/14/understanding-contexts-in-flask.html

PS If you planning to use url_for in tests, additional configuration required:

@classmethod
def setUpClass(cls)
    app.config['SERVER_NAME'] = 'localhost:5000'

Example

class ViewsTestCase(unittest.TestCase):
    @classmethod
    def setUpClass(cls):
        app.config['SERVER_NAME'] = 'localhost:5000'
        cls.client = app.test_client()

    def setUp(self):
        self.app_context = app.app_context()
        self.app_context.push()

    def tearDown(self):
        self.app_context.pop()

    def test_view_should_respond(self):
        r = self.client.get(url_for("index"))
        self.assertEqual(r.status_code, 200)

I needed to remove the .test_client() from my app to get this to work. — matthewlent, Apr 16 '15 at 22:24

score 8 · Answer 2 · answered Sep 05 '15 at 04:10

8

You can set app context manually:

app = Flask(__name__)
ctx = app.app_context()
ctx.push()

with ctx:
    pass

answered Sep 05 '15 at 04:10

Vayn

2,507
4
27
33

score 4 · Accepted Answer · answered Jul 22 '14 at 17:31

In case it's relevant, the reason I'm executing the tests from the parent directory is because I don't have the ability to add modules to site-packages, so I'm initiating all my code from the parent directory, where I've installed Flask, py.test, etc.

It turns out that this was very relevant. Because my code would eventually be run by a daemon, I wasn't sure I could depend on PYTHONPATH, and I didn't want to change sys.path at the top of each file. So, I was installing the package tarballs, and adding symlinks where necessary to make the packages importable.

It turns out the structure required to make the unittest code find flask was:

./Flask-0.10.1/
./flask -> Flask-0.10.1/flask/
./tmp1/flask -> ../Flask-0.10.1/flask/

The last line was required by unittest, and it was that symlink that broke py.test.

When I just put the packages in their own directory, and set the PYTHONPATH, everything works. If I can't control the environment to use PYTHONPATH for the daemon, I'll bite the bullet, and add the sys.path modication everywhere.

So, bottom line is, it was an installation problem.

You can use virtualenv with virtualenvwrapper to add folders to sys.path globally for the whole application and avoid doing this in code — varela, Nov 02 '15 at 10:36

"RuntimeError: working outside of application context" when unit testing with py.test

3 Answers3

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