The best way for any developer to have acces to testnet IOTX is to create a developer account on the IoTeX Developer Portal and claim test tokens in their personal profile.
Simply connect your wallet on IOTX testnet and start claiming test IOTX immediately.
Claim test IOTX from your Dev Portal profile
From faucet
Another way to obtain test IOTX tokens for users that may need them for different purposes, other than developing, is to request them on the IoTeX web faucet:
NOTE: This will soon be deprecated in favor of an alternative option in the dev portal.