How to apply integration tests (rather than unit tests) to a Flask RESTful API

Question

[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 foll

Answer 1

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]

Answer 2

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.

Answer 3

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

Answer 4

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.