channels: ChannelsLiveServerTestCase session cookie creation error

My functional tests use following code snippets to log user in:

def create_session_cookie(self, username, password):
    # First, create a new test user
    User = get_user_model()
    user = User.objects.create_user(username=username, password=password)

    # Then create the authenticated session using the new user credentials
    session = SessionStore()
    session[SESSION_KEY] = user.pk
    session[BACKEND_SESSION_KEY] = settings.AUTHENTICATION_BACKENDS[0]
    session[HASH_SESSION_KEY] = user.get_session_auth_hash()
    session.save()

    # Finally, create the cookie dictionary
    cookie = {
        'name': settings.SESSION_COOKIE_NAME,
        'value': session.session_key,
        'secure': False,
        'path': '/',
    }
    return cookie

def create_cookie_and_go_to_page(self, email):
    session_cookie = self.create_session_cookie(
        username=email, password='top_secret'
    )

    # visit some url in your domain to setup Selenium.
    # (404 pages load the quickest)
    self.browser.get(self.server_url + '/404.html')
    # add the newly created session cookie to selenium webdriver.
    self.browser.add_cookie(session_cookie)
    # refresh to exchange cookies with the server.
    self.browser.refresh()
    # This time user should present as logged in.
    self.browser.get(self.server_url)

and I use it as:

class DjangoTest(StaticLiveServerTestCase):

    def test_django(self):
        self.create_cookie_and_go_to_page('email@example.com')

Also I used to test my channels pages (installed with pip install git+git://github.com/django/channels.git@master#egg=channels) like this:

class ChannelsTest(ChannelsLiveServerTestCase):

    def test_channels(self):
        self.create_cookie_and_go_to_page('email@example.com')

, but with ChannelsLiveServerTestCase something has gone wrong in recent commits to master. It simply shows Bad Request (400) page after self.browser.get(self.server_url + '/404.html') call. If I revert to channels==2.0.2 from PyPI then it goes well, but css and js are broken with that version. I tried to locate error on a specific commit or dependency version, but without success.