Don't use "main"... the "account name" parameter has been deprecated according to the docs. try just using:
or
bitcoin-cli getbalance "*"
If you're still getting 0.00000000 using getbalance, then maybe it is simply because your testnode is not synced and it hasn't seen the transactions where your addresses receive the faucet payments. Try checking:
bitcoin-cli getnetworkinfo
and
bitcoin-cli getblockchaininfo
And make sure everything is as it should be (connections OK, number of blocks = current testnet blockheight etc)
EDIT: quite likely just because your node wasn't synced... TestNet can be a bit "odd" at times