I thought this was kinda obvious but, judging from other threads, seems I'm being original.
What do you do when you want to try a brand new god before going in against players? Don't go for jungle practice. It's basically useless. You can try your damage against bots without items and that's all.
Instead, start a custom game. Set it to 1v1, pick joust or conquest and fill the other space with a bot of your choice. You can try many things this way: a regular level 1 1500 start, a level 5 start for the ultimate, lots of money for a full build (the enemy will also start with a full build), level 20 for end-game stats. Pick a tanky god, like Hercules, and they'll build tanky.
In a custom game, unlike jungle practice, you can also learn something very important: your clear capacity against any enemy - see if you get underleveled against an Anubis or Neith, for example. Bots are stupid and easy to kill, but at least they move so you can learn how to aim your skillshots. They also attack you competently (meaning they land their stuff), so you can test your defense.
Of course, don't expect to be good with that. Just to understand the very basics without pissing off fellow players.