Mock authentication decorator in unittesting

Question

I wanted to mock validate_token decorator while writing unit test for one of view

#views.py
from third_part.module import vaidate_token
from setting import config
class myViews:
     @validate_token([config['issuer'], config['secret_key']])
     def get_data():
         #Do stuff
         return json.loads(data)

Here validate_token is a thirtd_party module to authorize request and the token is issued by third party so I don't want execute validate_token decorator for my tests

below are my sample test code.

test_views.py

@patch('views.validate_token', lambda x: x)
def test_get_data(self):
    endpoint = '/app/get_data'
    res = self.client.get(endpoint)
    assert res.status_code==200

I tried to mock while running tests
But its not working as expected, , its giving 401 error.

how can I mock/patch decorator for tests anything am missing here

Thanks in advance.

Answer 1

Here an example which can help you. Structure of files below.

app.py

from flask import Flask
from third_part.example import validate_token

app = Flask(__name__)

@app.route('/')
@validate_token()
def index():
    return 'hi'

if __name__ == '__main__':
    app.run(debug=True)

/third_part/example.py

from functools import wraps

def validate_token():
    def validate(func):
        @wraps(func)
        def wrapper(*args, **kwargs):
            raise Exception('Token error. Just for example')
            return func(*args, **kwargs)
        return wrapper
    return validate

tests.py:

from app import app

app.testing = True

def test_index():
    with app.test_client() as client:
        client.get('/')

Run our tests.py(just make sure that decorator works):

    @wraps(func)
    def wrapper(*args, **kwargs):
>       raise Exception('Token error. Just for example')
E       Exception: Token error. Just for example

First way how to skip decorator(using patch). tests.py:

from functools import wraps
from mock import patch

def mock_decorator():
    def decorator(f):
        @wraps(f)
        def decorated_function(*args, **kwargs):
            return f(*args, **kwargs)
        return decorated_function
    return decorator

patch('third_part.example.validate_token', mock_decorator).start()
# !important thing - import of app after patch()
from app import app

app.testing = True

def test_index():
    with app.test_client() as client:
        client.get('/')

Second way(without patch). tests.py:

from functools import wraps
from third_part import example

def mock_decorator():
    def decorator(f):
        @wraps(f)
        def decorated_function(*args, **kwargs):
            return f(*args, **kwargs)
        return decorated_function
    return decorator
# !important thing - import of app after replace
example.validate_token = mock_decorator

from app import app
app.testing = True

def test_index():
    with app.test_client() as client:
        client.get('/')

Run our test.py(in 2 ways):

tests.py .                                                               [100%]

=========================== 1 passed in 0.09 seconds ===========================

Summarize. As you can see, very important thing is when you replace the function. By the way, you trying to patch validate_token of views module, but not third_part.module

Hope this helps.