How to test a Flask/HTTP Cloud Function in Python ?

main.py

from flask import Flask, Request, make_response


def hello_http(request: Request):
    """HTTP Cloud Function.
    Args:
        request (flask.Request): The request object.
        <https://flask.palletsprojects.com/en/1.1.x/api/#incoming-request-data>
    Returns:
        The response text, or any set of values that can be turned into a
        Response object using `make_response`
        <https://flask.palletsprojects.com/en/1.1.x/api/#flask.make_response>.
    """
    # request_json = request.get_json()
    # request_args = request.args
    return make_response("oops", 400)

main_test.py

from flask import Flask, Request
from werkzeug.test import EnvironBuilder

from main import hello_http

app = Flask(__name__)


def test_main():
    with app.app_context():
        # This is the mock
        builder = EnvironBuilder(
            method='POST',
            json={'foo': 'bar'},
        )

        # Use the mock
        env = builder.get_environ()
        req = Request(env)

        # Test it
        res = hello_http(request=req)

        assert res.status_code == 400
        assert res.get_data(as_text=True) == "oops"

result

~/Sources/test-request-python via python-3.9.2 using ☁️  default/groups-terraform-sync-dtep 
➜ python3 -m pytest -vss .     
================================================================================ test session starts ================================================================================
platform linux -- Python 3.9.2, pytest-6.2.2, py-1.10.0, pluggy-0.13.1 -- /home/quentin/Sources/test-request-python/.direnv/python-3.9.2/bin/python3
cachedir: .pytest_cache
rootdir: /home/quentin/Sources/test-request-python
collected 1 item                                                                                                                                                                    

main_test.py::test_main PASSED

================================================================================= 1 passed in 0.05s =================================================================================