anchor.diff:  -define(MATCH_ANY,         "{{_}}").
   -define(SUB_BEGIN_TAG,     "{{>").
   -define(SUB_END_TAG,       "<}}").
  --define(ERROR,             "ERROR").
   -define(SCENARIO_TIMEOUT,  120000).
   -define(REQUEST_TIMEOUT,   20000).
   
  
positive.code: %%%   "{{_}}"     Match anything (i.e. no real validation, only check existence)
  %%%   "{{>key}}"  Store value of the whole string
  %%%               (key must be unique within testcase)
  %%%   "ERROR"     as a status code means we are expecting to get an error back
  %%%               instead of a proper http code.
  %%%   "{{<key}}"  Recall stored value.
  %%%   "{{>key<}" Substitute with value from SubVars list in run/3
  %%%
  
negative.code:              to_list(V), [{return, binary}, global]).
  
  %%%_* Validation -------------------------------------------------------
  validate(E = #response{}, A = #response{})           ->
    Result = [validate_status(E, A), validate_headers(E, A), validate_body(E, A)],
    case lists:filter(fun(X) -> X =/= pass end, lists:flatten(Result)) of
  