I said without foreknowledge though, most people probably kill at least a few things during the game, unless someone beforehand already decided they wanted one of their characters to be a purist, most people would fail the test.

As far as I know, the requirements for passing the test are no killing and no stealing and that is not that impossible to do if you dedicated your character to be a buffer/healer with no thievery. Consume a corpse to gain a Source Point, or steal a Source Point from a living character. source magic skills (bless, spirit vision, and source vampirism) in Divinity: Original Sin 2. Source Vampirism is located on under Memorised Skills and is considered an Innate Skill. Return to the Hall of Echoes once the second Source point is unlocked. I should note that theres a bug that lets you. Some people like to do purist runs, and it's not impossible to do it in this game. Source Vampirism is a Sourcery Skill in Divinity: Original Sin II It becomes obtainable during the quest Powerful Awakening. Careful for it will summon multiple enemies, and can use source skills like source vampirism and curse.

If you go by that criteria, then your character is evil regardless of what you do, because if you kill anyone, even out of defense or because the person/things were bad, you fail the test. Except those checks are pretty much impossible to pass legitimately without foreknowledge, i'm not counting the exploit you can do that allows you to pass them.