How to apply integration tests to a Flask RESTful API - python

[As per https://stackoverflow.com/a/46369945/1021819, the title should refer to integration tests rather than unit tests]
Suppose I'd like to test the following Flask API (from here):
import flask
import flask_restful
app = flask.Flask(__name__)
api = flask_restful.Api(app)
class HelloWorld(flask_restful.Resource):
def get(self):
return {'hello': 'world'}
api.add_resource(HelloWorld, '/')
if __name__ == "__main__":
app.run(debug=True)
Having saved this as flaskapi.py and run it, in the same directory I run the script test_flaskapi.py:
import unittest
import flaskapi
import requests
class TestFlaskApiUsingRequests(unittest.TestCase):
def test_hello_world(self):
response = requests.get('http://localhost:5000')
self.assertEqual(response.json(), {'hello': 'world'})
class TestFlaskApi(unittest.TestCase):
def setUp(self):
self.app = flaskapi.app.test_client()
def test_hello_world(self):
response = self.app.get('/')
if __name__ == "__main__":
unittest.main()
Both the tests pass, but for the second test (defined in the TestFlaskApi) class I haven't yet figured out how to assert that the JSON response is as expected (namely, {'hello': 'world'}). This is because it is an instance of flask.wrappers.Response (which is probably essentially a Werkzeug Response object (cf. http://werkzeug.pocoo.org/docs/0.11/wrappers/)), and I haven't been able to find an equivalent of the json() method for requests Response object.
How can I make assertions on the JSON content of the second response?

Flask provides a test_client you can use in your tests:
from source.api import app
from unittest import TestCase
class TestIntegrations(TestCase):
def setUp(self):
self.app = app.test_client()
def test_thing(self):
response = self.app.get('/')
assert <make your assertion here>
Flask Testing Docs

I've found that I can get the JSON data by applying json.loads() to the output of the get_data() method:
import unittest
import flaskapi
import requests
import json
import sys
class TestFlaskApiUsingRequests(unittest.TestCase):
def test_hello_world(self):
response = requests.get('http://localhost:5000')
self.assertEqual(response.json(), {'hello': 'world'})
class TestFlaskApi(unittest.TestCase):
def setUp(self):
self.app = flaskapi.app.test_client()
def test_hello_world(self):
response = self.app.get('/')
self.assertEqual(
json.loads(response.get_data().decode(sys.getdefaultencoding())),
{'hello': 'world'}
)
if __name__ == "__main__":
unittest.main()
Both tests pass as desired:
..
----------------------------------------------------------------------
Ran 2 tests in 0.019s
OK
[Finished in 0.3s]

What you're doing there is not unit testing. In every case, when using the requests library or the flask client, you're doing integration testing as you make actual http calls to the endpoints and test the interaction.
Either the title of the question or the approach is not accurate.

With Python3, I got the error TypeError: the JSON object must be str, not bytes. It is required to decode:
# in TestFlaskApi.test_hello_world
self.assertEqual(json.loads(response.get_data().decode()), {'hello': 'world'})
This question gives an explanation.

The response object from test_client has a get_json method.
There's no need for converting the response to json with json.loads.
class TestFlaskApi(unittest.TestCase):
def setUp(self):
self.app = flaskapi.app.test_client()
def test_hello_world(self):
response = self.app.get("/")
self.assertEqual(
response.get_json(),
{"hello": "world"},
)

Related

Return the same response model on two different endpoints on FastAPI

I am using FastAPI and I cannot view the documentation on the /docs endpoint when I have the same response model for two endpoints.
This is the code I use
import dataclasses
import fastapi
import uvicorn
app = fastapi.FastAPI()
#dataclasses.dataclass
class Response:
yo: str
#app.post('/one', response_model=Response)
def get_responses():
pass
#app.post('/two', response_model=Response) # When I remove this "Response", or I create a second class it works.
def send_responses():
pass
if __name__ == '__main__':
uvicorn.run(app, host='127.0.0.1')
This is the error it shows in the browser
This is the error it shows in the code
...
response = await func(request)
File "E:\Code\venvs\lib\site-packages\fastapi\applications.py", line 224, in openapi
return JSONResponse(self.openapi())
File "E:\Code\venvs\lib\site-packages\fastapi\applications.py", line 199, in openapi
self.openapi_schema = get_openapi(
File "E:\Code\venvs\lib\site-packages\fastapi\openapi\utils.py", line 418, in get_openapi
definitions = get_model_definitions(
File "E:\Code\venvs\lib\site-packages\fastapi\utils.py", line 32, in get_model_definitions
model_name = model_name_map[model]
KeyError: <class 'pydantic.dataclasses.Response'>
What am I doing wrong?
To summarize the comments: currently FastAPI seems to have problems when re-using the same dataclass. The solution would be to use the BaseModel of pydantic instead.
Below is the full working code, the only change is how the class "Response" is declared.
import dataclasses
import fastapi
import uvicorn
import pydantic
app = fastapi.FastAPI()
class Response(pydantic.BaseModel):
yo: str
#app.post('/one', response_model=Response)
def get_responses():
pass
#app.post('/two', response_model=Response)
def send_responses():
pass
if __name__ == '__main__':
uvicorn.run(app, host='127.0.0.1')

how to do unit test for functions inside of Resource class in flask-restful?

I am quite new to unit testing and relatively new to RESTful API development as well. I am wondering how to do unit test for functions inside Resource class in flask restful? I can do unit test for the endpoint's response but I don't know how to do testing for the individual functions inside the endpoint's controller class.
Below is my application code. It has 3 files including test:
api.py
controller_foo.py
test_controller_foo.py
# api.py
from flask import Flask
from flask_restful import Api
from .controller_foo import ControllerFoo
def create_app(config=None):
app = Flask(__name__)
app.config['ENV'] ='development'
return app
application = app = create_app()
api = Api(app)
api.add_resource(ControllerFoo, '/ctrl')
if __name__ == "__main__":
app.run(debug=True)
# controller_foo.py
from flask_restful import Resource
from flask import request
class ControllerFoo(Resource):
"""
basically flask-restful's Resource method is a wrapper for flask's MethodView
"""
def post(self):
request_data = self.handle_request()
response = self.process_request(request_data)
return response
def handle_request(self):
json = request.get_json()
return json
def process_request(self, data):
# do some stuffs here
return {'foo': 'bar'}
I am using unittest
# test_controller_foo.py
import unittest
from api import app
from .controller_foo import ControllerFoo
# initiating class to try testing but I don't know how to start
ctrl = ControllerFoo()
class ControllerFooTestCase(unittest.TestCase):
def setUp(self):
self.app = app
self.app.config['TESTING'] = True
self.client = app.test_client()
self.payload = {'its': 'empty'}
def tearDown(self):
pass
def test_get_response(self):
response = self.client.post('/ctrl', json=self.payload)
expected_resp = {
'foo': 'bar'
}
self.assertEqual(response.status_code, 200)
self.assertDictEqual(response.get_json(), expected_resp)
if __name__ == "__main__":
unittest.main()
I want to know how to properly do unit test for handle_request and process_request function
EDIT: Fixing out my buggy code. Thanks Laurent LAPORTE for the highlights.
There are several bugs in your code, so this is not easy to explain.
First of all, the recommended way to do testing with Flask (and Flask-Restful) is to use PyTest instead of unittest, because it is easier to setup and use.
Take a look at the documentation: Testing Flask Applications.
But, you can start with unittest…
note: you can have a confusion with your app module and the app instance in that module. So, to avoid it, I imported the module. Another good practice is to name your test module against the tested module: "app.py" => "test_app.py". You can also have a confusion with the controller module and the controller instance. The best practice is to use a more precise name, like "controller_foo" or something else…
Here is a working unit test:
# test_app.py
import unittest
import app
class ControllerTestCase(unittest.TestCase):
def setUp(self):
self.app = app.app
self.app.config['TESTING'] = True
self.client = self.app.test_client()
self.payload = {'its': 'empty'}
def test_get_response(self):
response = self.client.post('/ctrl', json=self.payload)
expected_resp = {'foo': 'bar'}
self.assertEqual(response.status_code, 200)
self.assertDictEqual(response.get_json(), expected_resp)
if __name__ == "__main__":
unittest.main()
As you can see, I also fixed the posted URL, in your application, the URL is "/ctrl", not "controller".
At this point, the test can run, but you have another error:
Ran 1 test in 0.006s
FAILED (errors=1)
Error
Traceback (most recent call last):
...
TypeError: process_request() takes 1 positional argument but 2 were given
If you take a look at your process_request() method, you can see that you missed the self parameter. Change it like this.
def process_request(self, data):
# do some stuffs here
return {'foo': 'bar'}
Your test should pass.
But, that not the right way to implement Flask-Restful controolers. Read the doc and use get and post methods…

Flask unit tests -- mocking up Aerospike DB

I have the following endpoint,
#developer_blueprint.route("/init_db", methods=["POST"])
def initialize_database():
try:
upload_data(current_app)
logger.debug("Database entries upload.")
return jsonify({"result": "Database entries uploaded."}), 201
except Exception as e:
return jsonify({"error": str(e)})
def upload_data(app):
with open("src/core/data/data.json") as data_file:
data = json.load(data_file)
try:
current_app.db.put(("somenamespace", "test", "default"), data, None)
except Exception as e:
raise e
I'm trying to figure out how to unit test this (we need to get coverage on our code).
Do I just mock up app.db? How can I do that?
Any suggestions would be appreciated.
It is not uncommon to mock database calls for unit testing using something like unittest.mock and then run Aerospike in a container or VM for end-to-end testing.
However, keep in mind that the Aerospike Python client library is written in C for better performance and thus it is not easy to do partial patching (aka "monkey patching"). For example, you will get a TypeError: can't set attributes of built-in/extension type if you try to simply patch out aerospike.Client.put.
One approach is to create a mock client object to replace or sub-class the Aerospike client object. The implementation of this mock object depends on your code and the cases you are testing for.
Take the following example code in which app.db is an instance of the Aerospike client library:
# example.py
import aerospike
import json
class App(object):
db = None
def __init__(self):
config = {'hosts': [('127.0.0.1', 3000)]}
self.db = aerospike.client(config).connect()
def upload_data(app):
with open("data.json") as data_file:
data = json.load(data_file)
try:
app.db.put(("ns1", "test", "default"), data, None)
except Exception as e:
raise e
if __name__ == "__main__":
app = App()
upload_data(app)
In writing unit tests for the upload_data function let's assume you want to test for a success case which is determined to mean that the put method is called and no exceptions are raised:
# test.py
from unittest import TestCase, main
from unittest.mock import PropertyMock, patch
from example import App, upload_data
from aerospike import Client, exception
class MockClient(Client):
def __init__(self, *args, **kwargs):
pass
def put(self, *args, **kwargs):
return 0
class ExampleTestCase(TestCase):
def test_upload_data_success(self):
with patch.object(App, 'db', new_callable=PropertyMock) as db_mock:
db_mock.return_value = client = MockClient()
app = App()
with patch.object(client, 'put') as put_mock:
upload_data(app)
put_mock.assert_called()
if __name__ == '__main__':
main()
In the test_upload_data_success method the App.db property is patched with the MockClient class instead of the aerospike.Client class. The put method of the MockClient instance is also patched so that it can be asserted that the put method gets called after upload_data is called.
To test that an exception raised by the Aerospike client is re-raised from the upload_data function, the MockClient class can be modified to raise an exception explicitly:
# test.py
from unittest import TestCase, main
from unittest.mock import PropertyMock, patch
from example import App, upload_data
from aerospike import Client, exception
class MockClient(Client):
def __init__(self, *args, **kwargs):
self.put_err = None
if 'put_err' in kwargs:
self.put_err = kwargs['put_err']
def put(self, *args, **kwargs):
if self.put_err:
raise self.put_err
else:
return 0
class ExampleTestCase(TestCase):
def test_upload_data_success(self):
with patch.object(App, 'db', new_callable=PropertyMock) as db_mock:
db_mock.return_value = client = MockClient()
app = App()
with patch.object(client, 'put') as put_mock:
upload_data(app)
put_mock.assert_called()
def test_upload_data_error(self):
with patch.object(App, 'db', new_callable=PropertyMock) as db_mock:
db_mock.return_value = MockClient(put_err=exception.AerospikeError)
app = App()
with self.assertRaises(exception.AerospikeError):
upload_data(app)
if __name__ == '__main__':
main()

python mock assert_called_with

I'm trying to understand the assert_called_with within mock but the code I wrote throws some error.
import os
import twitter
URL = "http://test.com"
def tweet(api, message):
if len(message) > 40:
message = message.strip("?.,.,.")
status = api.PostUpdate(message)
return status
def main():
api = twitter.Api(consumer_key=''
,consumer_secret='')
msg = 'This is test message'
tweet(api, msg)
if __name__ == '__main__':
main()
unittest
import unittest
from mock import Mock
import test
class TweetTest(unittest.TestCase):
def test_example(self):
mock_twitter = Mock()
test.tweet(mock_twitter,'msg')
mock_twitter.PostUpdate.assert_called_with('message')
if __name__ == '__main__':
unittest.main()
I'm trying to understand what assert_called_with does here?
According to the python documentation https://docs.python.org/3/library/unittest.mock.html#unittest.mock.Mock.assert_called_with
'This method is a convenient way of asserting that calls are made in a
particular way'
so it tests whether the parameters are being used in the correct way.
About the errors that you are receiving, I think the parameter you're passing is wrong. Its have to be something like this:
mock_twitter.PostUpdate.assert_called_with(message='msg')

tornado testing #tornado.web.authenticated

I'm trying to test tornado using AsyncHTTPTestCase. I want to test handlers marked with the #tornado.web.authenticated annotation. Because this handler requires authentication we must login first or somehow fool it in thinking we are authenticated in our test code
class HandlerToTest(BaseHandler):
#tornado.web.authenticated
def get(self):
self.render("hello.html", user=self.get_current_user() )
According to this article we can fudge the cookies. I have got this working but according to Ben Darnell tornado maintainer this is not recommended. Ben recommends using the CookieLib module but that requires the 'info' part of the response which we don't have.
Another blog post suggests mocking the get_current_user() call using mox. However I can not get the sample code in the blog working.
So my question is:
What is the best way of testing the handlers marked as authenticated? And can someone point me to a sample application?
Eventually got Mocks working. Don't know if this is the 'best way' but it might be useful to someone in the future. This code tests 2 handlers and mocks the get_current_user() call generated by #tornado.web.authenticated:
# encoding: utf-8
import os, os.path, sys
import tornado.web
import tornado.testing
import mox
class BaseHandler(tornado.web.RequestHandler):
def get_login_url(self):
return u"/login"
def get_current_user(self):
user_json = self.get_secure_cookie("user")
if user_json:
return tornado.escape.json_decode(user_json)
else:
return None
class HelloHandler(BaseHandler):
#tornado.web.authenticated
def get(self):
self.render("protected.html")
class Protected(tornado.web.RequestHandler):
def get_current_user(self):
# get an user from somewhere
return "andy"
#tornado.web.authenticated
def get(self):
self.render("protected.html")
class TestAuthenticatedHandlers(tornado.testing.AsyncHTTPTestCase):
def get_app(self):
self.mox = mox.Mox()
app = tornado.web.Application([
(r'/protected', Protected),
(r'/hello', HelloHandler)
])
return app
def tearDown(self):
self.mox.UnsetStubs()
self.mox.ResetAll()
def test_new_admin(self):
self.mox.StubOutWithMock(Protected, 'get_current_user', use_mock_anything=True)
Protected.get_current_user().AndReturn("test_user")
self.mox.ReplayAll()
resp = self.fetch('/protected')
self.assertEqual(resp.code, 200)
self.mox.VerifyAll()
def test_hello_page(self):
self.mox.StubOutWithMock(HelloHandler, 'get_current_user', use_mock_anything=True)
HelloHandler.get_current_user().AndReturn("test_user")
self.mox.ReplayAll()
resp = self.fetch('/hello')
self.assertEqual(resp.code, 200)
self.assertIn( "Hello", resp.body )
self.mox.VerifyAll()
This Torando utils library also allows you to test authenticated handlers: tornado_utils/http_test_client.py
In my case simply works:
BaseHandler.get_current_user = lambda x: {'username': 'user', 'email': 'user#ex.com'}

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