anchor.diff:                      167,173,228,112,201,249,157,157,78,64,8,128,168,111,29,73,
                       187,68,75,98,241,26,158,187,100,187,207,235,115,254,243>>
         }.
  -
  -key_blocks_count(Blocks) ->
  -    length(lists:filter(fun aec_blocks:is_key_block/1, Blocks)).
  
positive.code: %% Test cases
  %% ============================================================
  siblings_on_key_block(Config) ->
      MBC = ?config(micro_block_cycle, Config),
      aecore_suite_utils:start_node(dev1, Config),
      aecore_suite_utils:start_node(dev2, Config),
  
  
negative.code: %% ============================================================
  %% Helpers
  %% ============================================================
  add_spend_tx(Node, Amount, Fee, Nonce, TTL, Sender, Recipient) ->
      SenderId = aec_id:create(account, maps:get(pubkey, Sender)),
      RecipientId = aec_id:create(account, Recipient),
  