I run: ./bitcoind -testnet -datadir=$(pwd)/.bitcoinTEST -printtoconsole
... and I see:
Bitcoin version v0.6.0.99-unk-beta (Apr 11 2012, 15:10:15) Default data directory /Users/gavin/Library/Application Support/Bitcoin Loading addresses... dbenv.open LogDir=/Users/gavin/src/integration_btc/src/.bitcoinTEST/database ErrorFile=/Users/gavin/src/integration_btc/src/.bitcoinTEST/db.log
... which is wrong, the db env should be .bitcoinTEST/testnet/...