I consider myself to have aphantasia (cannot visualize anything in my mind, except when dreaming) and I think I could still pass the test you mention.
If I imagine a car, I can imagine its features, and of course color being a quite salient feature I would probably assign it a color (e.g. I could imagine a red Ferrari, or a black limo). It's just that I wouldn't see it, there wouldn't be anything in my mind similar to the actual experience of seeing a red object, I would just think about the "concept" of the car being red (hard to explain).
So far I've never found a way in which aphantasia really manifests externally or can be measured externally in a more or less reliable way. Which is why I'm still not 100% sure that people who claim not to be aphantasiacs aren't just exaggerating or taking metaphors too literally...
People without aphantasia can recall details about things that they didn't notice when they first looked at it, because they can "look at it again" in their mind.
I can't recall anything I didn't actively notice while looking. If you stop me when I'm leaving a grocery store and ask me questions about the cashier, I won't be able to tell you their hair color or what kind of clothes they were wearing. Sometimes I won't even be able to tell you if they were tall or fat or any other physical adjectives.
If I imagine a car, I can imagine its features, and of course color being a quite salient feature I would probably assign it a color (e.g. I could imagine a red Ferrari, or a black limo). It's just that I wouldn't see it, there wouldn't be anything in my mind similar to the actual experience of seeing a red object, I would just think about the "concept" of the car being red (hard to explain).
So far I've never found a way in which aphantasia really manifests externally or can be measured externally in a more or less reliable way. Which is why I'm still not 100% sure that people who claim not to be aphantasiacs aren't just exaggerating or taking metaphors too literally...