Flask REST API - parameter parsing

from flask import Flask, request
from flask_restful import Api, Resource, reqparse

app = Flask(__name__)

api = Api(app)


class Echo(Resource):
    def get(self):
        parser = reqparse.RequestParser()
        parser.add_argument('text', help='Type in some text')
        args = parser.parse_args()
        return { "res": f"Text: {args['text']}" }

    def post(self):
        parser = reqparse.RequestParser()
        parser.add_argument('text', help='Type in some text')
        args = parser.parse_args()
        return { "Answer": f"You said: {args['text']}" }


api.add_resource(Echo, '/echo')

import api

def test_echo():
    web = api.app.test_client()

    rv = web.get('/echo?text=hello')
    assert rv.status == '200 OK'
    assert rv.headers['Content-Type'] == 'application/json'
    assert rv.json ==  {'res': 'Text: hello'}

    rv = web.post('/echo', data={'text': 'ciao'})
    assert rv.status == '200 OK'
    assert rv.headers['Content-Type'] == 'application/json'
    assert rv.json == {'Answer': 'You said: ciao'}


    # If the parameter is missing the parser just returns None
    rv = web.get('/echo')
    assert rv.status == '200 OK'
    assert rv.headers['Content-Type'] == 'application/json'
    assert rv.json ==  {'res': 'Text: None'}