Testnet Simulation on 2018-01-28 @ block 506265:

./dump.py BITCOIN_DATADIR OUTPUT_DIR --verbose=True --reindex=True --bitcoind BITCOIND_PATH --blockheight=506265

Run like: ./dump.py ~/.bitcoin OUTPUT_DIR --verbose=True --reindex=True --bitcoind ~/src/bitcoin/src/bitcoind --blockheight=504000