'Create a request with the given value as the value of an
I{Authorization} header and perform resource traversal with it,
starting at C{self.wrapper}.  Assert that the result is a 401 response
code.  Return a L{Deferred} which fires when this is all done.'

def _invalidAuthorizationTest(self, response):

    self.credentialFactories.append(BasicCredentialFactory('example.com'))
    request = self.makeRequest([self.childName])
    request.requestHeaders.addRawHeader('authorization', response)
    child = getChildForRequest(self.wrapper, request)
    d = request.notifyFinish()
    def cbFinished(result):
        self.assertEqual(request.responseCode, 401)
    d.addCallback(cbFinished)
    request.render(child)
    return d
