No. The testing period has come to an end although there will be another round for a major upgrade in the future. the 1 year for free is that if you have a genuine Windows 7, 8, or 8.1 license, you can receive Windows 10 for free via the upgrade route and it is yours to keep. If you don't claim the offer within one year, then you must buy an upgrade license if you wish to get Windows 10.
As with all OS installations, it wipes out your previous one. Every single upgrade tells you to have a backup plan ready (which is best practice).
I've upgraded via ISO and the built-in upgrade. On restart when the setup should have launched I got a boot error ending up by being forced to make a fresh install. Luckily I've expected something like this happens and so I was prepared.
I recommend a complete backup before upgrading including a rescue disk but again there is no need to upgrade NOW. There are no DX12 games and you still need a DX12 graphic card and the free upgrade is available for 1 year.
I just did because I had to reinstall my OS so or so and I'm thankful about the reset option Windows 8 and Windows 10 have which replaces a fresh install because it not only uninstall all apps but also clean the registry and appdata folder completely so yeah, its nearly as good as a fresh install. So I decided to choose Windows 10 instead of Windows 7 again.