Sounds like an OK test to me. Great (senior) developers should be able to do that kind of thing. Categorizing yourself exclusively as "a Ruby developer" is a career trap.
And a lucrative one at that.
No engineer that makes 7 figures calls themselves a ruby developer with the exception of DHH.
Assuming that high earners are offsetting that to the higher end, most people aren't making 6 figures, and the bar isn't which language they're programming in.
$132,270
This means half of all full time employed devs are higher, and half are lower. The mean is more skewed by higher earners but is similar:
$138,110
It also varies quite widely by geographic location, from a mean high of $173,780 in California to only $125,890 in Texas, from $199,800 in San Jose to $132,500 in Austin to $98,960 in rural Kansas (where I have actually developed software before!)
The short of it is, the vast majority of software developers do not make the top salaries. Even L6 is rare within the top tier of tech. There is a lot of delusion in this field around pay, so it's important to be well informed. As a field we are still very well paid compared to most other jobs especially considering our safe working conditions and lack of needed credentials and education. Compared to most of the work on this planet, it's still a goldmine.