Why did I not test out of any skills? I took the Italian test...
and I got every single answer right except 3. 3. And it says I didn't test out of any skills. This is ridiculous given I know the basics in the Italian language.
When I took the French test I had gotten 5 or 6 questions wrong, and I passed 9 skills.
Is this a bug?
The test is adaptive, and harsh.
(Where harsh is defined by: it limits you below your first mistake, and then makes a new lower limit for each mistake after that. Which means that it optimistically believes you are giving your best performance when you take it, which is not necessarily true.)
My experiences and observations go as follows (although Duolingo tweak things from time to time, and put users into testgroups where functions perform differently):
It starts off with questions from skills near the start of the tree. If you get these right, all well and good, it adapts to asks harder questions. But if you get one of these easy questions wrong, it adapts to limit your ability to test out as no further than a little before where you got a question wrong; the remaining questions are then from before that point, and if you get any more of them wrong, well, the algorithm then cuts your testing-out back even further.
So, if you get one of the first few questions wrong, it will often mean you won't test out of any skills. Whereas if you get the first 14 or so questions right, but not the last 6, you will still have tested out of a significant number of skills.
As well as resetting and retesting, if you find it is still holding you back further than you think it should, if you have a mobile device you could try resetting online, then testing out using the mobile app, which can often prove easier.
It could be a bug. Reset your tree and retest. That's what I did once with the Spanish tree.