According to Google, the test will affect less than 0.5% of the internet users. In addition, even if IPv6 will be enabled for 24 hours, the old IPv4 will continue to be available.
How you can test your IPv6 connectivity?
There is a Google page to tests your connection and detects IPv6 connectivity issues. You can also test your IPv6 connectivity by going here. For your information, “Google has been supporting IPv6 since early 2008, when they first began offering search over IPv6. Since then they’ve brought IPv6 support to YouTube and have been helping ISPs to enable Google over IPv6 by default for their users”. [via]
