anchor.diff:  then([i, upgrade, the, connection, with, a, websocket, handshake], _State, _) ->
     receive
       {client_headers, Headers} ->
  -      io:format("H ~w ~n", [Headers])
  +      ok
     end,
  -  false.
  +  assert_that("Upgrade", is(get_header("connection", Headers))).
   
   %
   % Mock a http server
  
positive.code: 
  %-export([setup/0, teardown/1, given/3, then/3]).
  -compile([export_all]).
  
  setup()->
    start_http_server(self(), 8080),
  
negative.code:       Acc
    end.
  
  wait(_Socket)->
    false.
  
  get_header(Key, Headers) ->
    proplists:get_value(Key, Headers).
  