It looks like Azure is planning to test way more than three blockchains.

They are partnering so far with Ethereum, Ripple, Syscoin, Emercoin, Eris, CoinPrism, BitPay, Augur, Slock.it, and Lisk. Just a partial list, and some of these are DApps based on Ethereum.

Source: Marley Gray, Azure Director, Microsoft
https://azure.microsoft.com/en-us/blog/author/marleyg/