anchor.diff:  
   block_chain_test_() ->
       {foreach,
  -     fun() -> {ok, Pid} = aec_chain:start_link(fake_genesis_block()), Pid end,
  +     fun() -> {ok, Pid} = aec_chain:start_link(genesis_block()), Pid end,
        fun(_ChainPid) -> ok = aec_chain:stop() end,
        [{"Build chain with genesis block plus 2 headers, then store block corresponding to top header",
          fun() ->
                  %% Check chain is at genesis.
  -               B0 = fake_genesis_block(),
  +               B0 = genesis_block(),
                  BH0 = aec_blocks:to_header(B0),
                  ?assertEqual({ok, BH0}, aec_chain:top_header()),
   
  
positive.code: %% Cover unhappy paths not covered in any other tests.
  unhappy_paths_test_() ->
      {foreach,
       fun() -> {ok, Pid} = aec_chain:start_link(fake_genesis_block()), Pid end,
       fun(_ChainPid) -> ok = aec_chain:stop() end,
       [{"Get header by hash - case not found",
         fun() ->
                 %% Check chain is at genesis.
                 B0 = fake_genesis_block(),
                 BH0 = aec_blocks:to_header(B0),
                 ?assertEqual({ok, BH0}, aec_chain:top_header()),
  
  
negative.code: -include("common.hrl").
  -include("blocks.hrl").
  
  genesis_block() ->
      aec_genesis:genesis_block_as_deserialized_from_network().
  
  top_test_() ->
      {foreach,
       fun() -> {ok, Pid} = aec_chain:start_link(genesis_block()), Pid end,
       fun(_ChainPid) -> ok = aec_chain:stop() end,
       [{"Initialize chain with genesis block, then check top block with related state trees",
         fun() ->
                 GB = genesis_block(),
                 ?assertEqual({ok, GB}, aec_chain:top_block()),
  
                 {ok, Top} = aec_chain:top(),
  