anchor.diff:  % -> "old" entries should be copied to the snapshot-db in copy-on-write fashion
   -spec test_rdht_tx_read_validate_db_copy(any()) -> ok.
   test_rdht_tx_read_validate_db_copy(_) ->
  -    Db = ?TEST_DB:init_snapshot(?TEST_DB:new()),
  -    EntryKey = db_entry:new(?KEY("key"), ?VALUE("val"), 1),
  -    Db = ?TEST_DB:set_entry(Db, EntryKey),
  +    Db = ?DB:init_snapshot(?DB:new()),
  +    EntryKey = db_entry:new(?KEY("key"), ?VALUE("val"), 1),
  +    Db = ?DB:set_entry(Db, EntryKey),
       TLogEntry = tx_tlog:new_entry(?read, ?KEY("key"), 2, ?ok, 1, ?value, ?VALUE("new_val")),
       {NewDb, _Vote} = rdht_tx_read:validate(Db, 1, TLogEntry),
  -    ?equals(?TEST_DB:get_snapshot_entry(NewDb, ?KEY("key")),
  +    ?equals(?DB:get_snapshot_entry(NewDb, ?KEY("key")),
               {true, EntryKey}), % no readlocks in snap db
  -    ?equals(?TEST_DB:get_entry2(NewDb, ?KEY("key")),
  +    ?equals(?DB:get_entry2(NewDb, ?KEY("key")),
               {true, db_entry:inc_readlock(EntryKey)}), % 1 readlock in live db
       ok.
   
  
positive.code: % snapshot number in entry equals local number -> prepared
  -spec test_rdht_tx_write_validate_should_prepare(any()) -> ok.
  test_rdht_tx_write_validate_should_prepare(_) ->
      Db = ?TEST_DB:init_snapshot(?TEST_DB:new()),
      Db = ?TEST_DB:set_entry(Db, db_entry:new(?KEY("key"), ?VALUE("val"), 1)),
      TLogEntry = tx_tlog:new_entry(?write, ?KEY("key"), 1, ?ok, 4711, ?value, ?VALUE("val")),
      {_NewDb, Vote} = rdht_tx_write:validate(Db, 4711, TLogEntry),
      ?equals(Vote, ?prepared),
  
negative.code: % snapshot number in entry less than local number -> abort
  -spec test_rdht_tx_read_validate_should_abort(any()) -> ok.
  test_rdht_tx_read_validate_should_abort(_) ->
      Db = ?DB:init_snapshot(?DB:new()),
      Db = ?DB:set_entry(Db, db_entry:new(?KEY("key"), ?VALUE("val"), 1)),
      TLogEntry = tx_tlog:new_entry(?read, ?KEY("key"), 1, ?ok, 1, ?value, ?VALUE("new_val")),
      {_NewDb, Vote} = rdht_tx_read:validate(Db, 5, TLogEntry),
      ?equals(Vote, ?abort),
  