I don't think this is a very reliable test, and it even verges on misleading, as there is a degree of complexity that may lead people who do not have aphantasia to believe that they do have the condition. I think this line of thinking with your "test" has been what has led some people in the comments to say that they believe that the condition may just be a result of miscommunication on what mental visualization entails, since they believe that those who claim to have aphantasia believe that they have the condition due to not meeting a threshold of visualization.
However, it appears that for people who actually have the condition, visualization never gets to any specificity. One could be unable to answer a single one of the questions on your test, yet that does not necessarily mean they have aphantasia, as aphantasia is not the lack of detail in visualization, but the lack of any visualization at all. Some people who have aphantasia have attested in these comments that they cannot picture anything in their minds at all. Many of them attest that they don't even visualize when dreaming.
However, it appears that for people who actually have the condition, visualization never gets to any specificity. One could be unable to answer a single one of the questions on your test, yet that does not necessarily mean they have aphantasia, as aphantasia is not the lack of detail in visualization, but the lack of any visualization at all. Some people who have aphantasia have attested in these comments that they cannot picture anything in their minds at all. Many of them attest that they don't even visualize when dreaming.