Running Single Flask Unittest Passes but Running All Tests Gives AssertionError

Question

I have Flask application that uses the Flask-Restful library. I have a my app structure set up like so:

server
 application.py
- app
   users.py
  - tests
     test_users.py
- common
   tests.py

My application set up is defined in application.py. I'm using the Factory pattern.

api = Api(prefix='/api/v0')

def create_app(config_filemane):
  flask_app = Flask(__name__)
  flask_app.config.from_object(config_filemane)
  db.init_app(flask_app)

  from app.users import add_user_resources
  add_user_resources()
  api.init_app(flask_app)

  return flask_app

In users.py, I have my Resource subclasses:

class UserListAPI(Resource):

  def __init__(self):
    super(UserListAPI, self).__init__()

  def get(self):

  def post(self):


class UserAPI(Resource):

  def __init__(self):
    super(UserAPI, self).__init__()

  def get(self, id):

  def put(self, id):

  def delete(self, id):

def add_user_resources():
  api.add_resource(UserListAPI, '/users', endpoint='users')
  api.add_resource(UserAPI, '/users/<id>', endpoint='user')

Please see my github page for the full code.

I set up my unit test class in common/tests.py following this snippet.

I run my tests using Nose. When I run any single test, it passes. When I run all tests using

$ nosetests

I get the following error:

AssertionError: View function mapping is overwriting an existing endpoint function: users

I think the error is being caused by the test runner trying to register another Flask-Restful resource after they have already been registered. In users.py, I have two Resource subclasses: UsersListAPI and UsersAPI. (If you see the github page, I also have the same setup in trips.py.)

I thought that running a single TestCase would not raise the error, because I'm calling _pre_setup() in the base case once for the TestCase, where the test app is created but I still get the error if, for instance, I run the test:

$ nosetests app.tests.test_users:UsersTest

I still get the AssertionError.

Any thoughts?

Edit: Here are my test files.

The base test file at common/tests.py:

from flask.ext.testing import TestCase
from unittest import TestCase

from application import create_app

class BaseTestCase(TestCase):

    def __call__(self, result=None):
        self._pre_setup()
        super(BaseTestCase, self).__call__(result)
        self._post_teardown()

    def _pre_setup(self):
        self.app = create_app('settings_test')
        self.client = self.app.test_client()
        self._ctx = self.app.test_request_context()
        self._ctx.push()

    def _post_teardown(self):
        self._ctx.pop()

Note I'm importing TestCase from both flask.ext.testing and unittest, obviously not both at the same time when actually running the tests. When I import from flask.ext.testcase, the single test fails. Importing from unittest the single test passes:

$ nosetests app.tests.test_users:UsersTest.test_get_all_users

In both cases, running all tests or just the UsersTest test case, the tests fail. The actual test file, test_users.py is very long. I'll provide it as a gist. I've removed all superfluous code and left only two tests. If you would like to see the full test file, it is at my github repo.

Answer 1

Figured it out:

I have to move the line api = Api(prefix='/api/v0') into the function create_app and moved the add_resource functions into create_app as well:

def create_app(config_filemane):
  flask_app = Flask(__name__)
  ...
  api = Api(prefix='/api/v0')
  api.add_resource(UserListAPI, '/users', endpoint='users')
  api.add_resource(UserAPI, '/users/<id>', endpoint='user')
  ...
  return flask_app

The api object is no longer global but I don't think I'll need to elsewhere.