Newsflash! There's no test. It's not about you. If you've got anxieties about whiteness (all white people have them, BTW, especially the ones that think they don't), maybe do something entertaining or productive with it. Y'know, like Larry David.
Seriously though - racism is structure and practice, not nature. But a certain commitment to the practice of it will justifiably earn someone a label. If they double down, the label might stick. Stop worrying about whether you're racist as if you might discover or reveal sone kind of immutable racist core at the centre of your being - I promise you there isn't. In the context in which the present row kicked off, we were talking about the climate crisis. The point is not mainly that equitable, democratic, racially just solutions are morally right, but that they are the only way out for everyone. The alternative is some kind of eco-fascist dystopia where a global elite (which will be mainly white) deploys violent authoritarian means to protect itself from an increasingly desperate populace (which will be predominantly PoC). We have people hereabouts who are advocating for the latter.