anchor.diff:  -export([initial_state/0,
            initial_state_data/0,
            next_state_data/5,
  +         dynamic_precondition/4,
            precondition/4,
            postcondition/5]).
   
  
positive.code:       {call, ?MODULE, init_backend, [Backend, Volatile, Config]}}].
  
  running(#qcst{backend=Backend,
                s=State}) ->
      [
       {history, {call, Backend, put, [bucket(), key(), index_specs(), val(), State]}},
       {history, {call, Backend, get, [bucket(), key(), State]}},
       {history, {call, Backend, delete, [bucket(), key(), [], State]}},
       {history, {call, Backend, fold_buckets, [fold_buckets_fun(), get_fold_buffer(), g_opts(), State]}},
       {history, {call, Backend, fold_keys, [fold_keys_fun(), get_fold_buffer(), fold_keys_opts(), State]}},
       {history, {call, Backend, fold_objects, [fold_objects_fun(), get_fold_buffer(), g_opts(), State]}},
  
negative.code: 
  %% Helpers
  -export([drop/2,
           delete/5,
           init_backend/3]).
  
  -define(TEST_ITERATIONS, 50).
  