anchor.diff:      ?assertEqual({ok, BH2}, get_header(B2H, State2)),
       ?assertEqual(error, get_header(B1H, State0)),
       ?assertEqual(error, get_header(B2H, State0)),
  -    ?compareBlockResults({ok, B0}, get_block(B0H, State2)), %% TODO Check state trees too.
  -    ?compareBlockResults({ok, B1}, get_block(B1H, State2)), %% TODO Check state trees too.
  -    ?compareBlockResults({ok, B2}, get_block(B2H, State2)), %% TODO Check state trees too.
  +    ?compareBlockResults({ok, B0}, get_block(B0H, State2)),
  +    ?compareBlockResults({ok, B1}, get_block(B1H, State2)),
  +    ?compareBlockResults({ok, B2}, get_block(B2H, State2)),
       ?assertEqual(error, get_block(B1H, State0)),
       ?assertEqual(error, get_block(B2H, State0)),
   
  
positive.code:     ?assertEqual(BH2, top_header(State2)),
  
      %% Check highest block
      ?compareBlockResults({ok, B0}, {ok, top_block(State0)}), %% TODO Check state trees too.
      ?compareBlockResults({ok, B1}, {ok, top_block(State1)}), %% TODO Check state trees too.
      ?compareBlockResults({ok, B2}, {ok, top_block(State2)}), %% TODO Check state trees too.
  
      %% Check by hash.
      ?assertEqual({ok, BH0}, get_header(B0H, State2)),
  
negative.code:     ?assertEqual({ok, BH0}, get_header_by_height(0, State2)),
      ?assertEqual({ok, BH1}, get_header_by_height(1, State2)),
      ?assertEqual({ok, BH2}, get_header_by_height(2, State2)),
      ?compareBlockResults({ok, B0}, get_block_by_height(0, State2)),
      ?compareBlockResults({ok, B1}, get_block_by_height(1, State2)),
      ?compareBlockResults({ok, B2}, get_block_by_height(2, State2)),
      ?assertEqual({error, chain_too_short}, get_block_by_height(3, State2)).
  
  basic_access_missing_blocks() ->
  