Bitcoind clear / reset my testnet to retest some things I'm running bitcoind on centos and want to reset my testnet. I tested one way and now I want to test something else a different way.

For example, I want to clear it so when I do:

bitcoin-cli listaccounts


No accounts are returned.

AND

bitcoin-cli listtransactions


No transactions are returned.

What is the easiest way to do this?
Delete the wallet.dat file in your testnet datadir and restart Bitcoin Core. Note that this will destroy all of your coins.