Unittesting cherrypy webapp

Question

I recently had to rewrite our rest api, and made the switch from Flask to Cherrypy (mostly due to Python 3 compatibility). But now I\'m stuck trying to write my unit tests, Flas

Answer 1

I found the answer from Sylvain Hellegouarch to be super helpful in figuring this out, but it uses Python 2. I adapted their answer to use Python 3:

import io
import unittest
import urllib
import urllib.parse

import cherrypy
from cherrypy.lib import httputil

local = httputil.Host('127.0.0.1', 50000, '')
remote = httputil.Host('127.0.0.1', 50001, '')

class Root(object):
    @cherrypy.expose
    def index(self):
        return 'hello world'

    @cherrypy.expose
    def echo(self, msg):
        return msg

def setUpModule():
    cherrypy.config.update({'environment': 'test_suite'})

    # prevent the HTTP server from ever starting
    cherrypy.server.unsubscribe()

    cherrypy.tree.mount(Root(), '/')
    cherrypy.engine.start()

setup_module = setUpModule

def tearDownModule():
    cherrypy.engine.exit()

teardown_module = tearDownModule

class BaseCherryPyTestCase(unittest.TestCase):
    def webapp_request(self, path='/', method='GET', **kwargs):
        headers = [('Host', '127.0.0.1')]
        qs = fd = None

        if method in ['POST', 'PUT']:
            qs = urllib.parse.urlencode(kwargs)
            headers.append(('content-type', 'application/x-www-form-urlencoded'))
            headers.append(('content-length', f'{len(qs)}'))
            fd = io.BytesIO(qs.encode())
            qs = None
        elif kwargs:
            qs = urllib.parse.urlencode(kwargs)

        # Get our application and run the request against it
        app = cherrypy.tree.apps['']
        # Let's fake the local and remote addresses
        # Let's also use a non-secure scheme: 'http'
        request, response = app.get_serving(local, remote, 'http', 'HTTP/1.1')
        try:
            response = request.run(method, path, qs, 'HTTP/1.1', headers, fd)
        finally:
            if fd:
                fd.close()
                fd = None

        if response.output_status.startswith(b'500'):
            print(response.body)
            raise AssertionError('Unexpected error')

        # collapse the response into a bytestring
        response.collapse_body()
        return response

class TestCherryPyApp(BaseCherryPyTestCase):
    def test_index(self):
        response = self.webapp_request('/')
        self.assertEqual(response.output_status, b'200 OK')
        # response body is wrapped into a list internally by CherryPy
        self.assertEqual(response.body, [b'hello world'])

    def test_echo(self):
        response = self.webapp_request('/echo', msg='hey there')
        self.assertEqual(response.output_status, b'200 OK')
        self.assertEqual(response.body, [b'hey there'])

        response = self.webapp_request('/echo', method='POST', msg='hey there')
        self.assertEqual(response.output_status, b'200 OK')
        self.assertEqual(response.body, [b'hey there'])