Stay tuned: the testnet is a mess right now. Another genesis block reset might be needed to fix it, there have been several blockchain-splitting changes and there are several different versions of the blockchain competing (with/without the difficulty change, with/without the duplicate coinbase change, and with/without BIP16 support).
In the meantime, testing with a testnet-in-a-box or private testnet is a good way to go:
https://sourceforge.net/projects/bitcoin/files/Bitcoin/testnet-in-a-box/