The following two code snippets should do the same thing or the former should throw an exception if GetHTTPResponses is called more than once after a url is loaded:

t.LoadURL(foo)
t.assertEqual(t.GetHTTPResponses())
for response in t.GetHTTPResponses():
  ...

t.LoadURL(foo)
responses = t.GetHTTPResponses()
t.assertEqual(2, responses)
for response in t.GetHTTPResponses():
  ..