How to send requests with JSONs in unit tests

Question

I have code within a Flask application that uses JSONs in the request, and I can get the JSON object like so:

Request = request.get_json()

This has been working fine, however I am trying to create unit tests using Python's unittest module and I'm having difficulty finding a way to send a JSON with the request.

response=self.app.post('/test_function', 
                       data=json.dumps(dict(foo = 'bar')))

This gives me:

>>> request.get_data()
'{"foo": "bar"}'
>>> request.get_json()
None

Flask seems to have a JSON argument where you can set json=dict(foo='bar') within the post request, but I don't know how to do that with the unittest module.

Answer 1

UPDATE: Since Flask 1.0 released flask.testing.FlaskClient methods accepts json argument and Response.get_json method added, see example.

for Flask 0.x you may use receipt below:

from flask import Flask, Response as BaseResponse, json
from flask.testing import FlaskClient
from werkzeug.utils import cached_property


class Response(BaseResponse):
    @cached_property
    def json(self):
        return json.loads(self.data)


class TestClient(FlaskClient):
    def open(self, *args, **kwargs):
        if 'json' in kwargs:
            kwargs['data'] = json.dumps(kwargs.pop('json'))
            kwargs['content_type'] = 'application/json'
        return super(TestClient, self).open(*args, **kwargs)


app = Flask(__name__)
app.response_class = Response
app.test_client_class = TestClient
app.testing = True

Answer 2

Changing the post to

response=self.app.post('/test_function', 
                       data=json.dumps(dict(foo='bar')),
                       content_type='application/json')

fixed it.

Thanks to user3012759.