Make testing resource methods easier by creating arbitrary req/resp

It can be useful when you want to test a resource method in isolation to manually create a Request and Response object and pass them directly to the resource method.

def test_my_resource():
    resource = MyResource()
    req, resp = Request(helpers.create_environ()), Response()
    resource.on_get(req, resp)

There are some gotchas with manually creating the environ and it could be much easier.

• Provide a global method in testing.helpers which creates a Request and Response object.
  • Enable passing json, body, and stream
  • Automatically set Content-Length
  • Do best effort to set Content-Type
  • Enable passing arbitrary WSGI envs
• Create a method on TestClient which will utilize the global method but fill in some of the environment details and utilize application specific Request and Response.

def create_test_request_response(json: dict = None, body: string = None, context: dict = None, **env):
    env['body'] = (
        (body if body is not None else None)
        or (json.dumps(json) if json else '')
    )

    env = falcon.testing.create_environ(**env,)
    req = falcon.Request(env)
    req.context.update(context or {})
    return (req, falcon.Response())

def test_my_resource():
    resource = MyResource()
    req, resp = create_test_request_response(json={'hello': 'world'})
    resource.on_get(req, resp)

[kgriffs]

As it turns out, I need this for dual-testing ASGI/WSGI so I’m working on it as part of the ASGI branch.

[vytas7]

The remaining work items and documentation improvements were deferred to https://github.com/falconry/falcon/issues/1793.