A brand new feature is available for testing in the Test Client: Minecraft Snapshot management!
The Curse Client can help make Snapshot management a breeze -- Simply click "Get It" beside the Snapshot you'd like to test, and the Client will download that specific version to a separate folder from your release install, allowing for you to test without fear of save corruption! You can switch between any released snapshot at any time, and can additionally copy your Worlds over from your release version of Minecraft for even more specialized testing!
In addition, the "My Textures" and "Get More Textures" tabs are available on this install, making texture pack testing a breeze.
This beta version of the Snapshot feature can be tested on the test version of the Curse Client, which can be found here. Please note that once testing is done, it is advised to resume using the release version of the Client.