In my company we see a senior as someone who can help increase the leverage of juniors.

Another definition I’ve seen is “a senior developer is a developer who can turns other developers into senior developers”

Whereas someone who can autonomously get shit done (and may or may not be good at the earlier definitions) is a “contractor”.

The article makes it pretty clear that the exercise is a conversation, not a test. It’s not just seeing what they know, it’s finding out if they can carry on a pleasant conversation. It’s finding out if they can discuss a technical topic beyond telling the other person to “Google it.” In many organizations a Senior is responsible for helping the Juniors become Seniors — a responsibility not well suited to the autonomous lone wolf.

The way the author writes and answers questions in the comments shows he does actually see it as a test.

> Note that since our technical discussion is a conversation. I don’t expect a perfect answer from anyone. If I hear some right keywords, I know that the candidate knows the concept, and I try to push them in the right direction

I.e. if you don't know the concept you don't pass.

And in a comment:

> I would much rather hire an all-rounder with deep knowledge of HTML/CSS/JS rather than a particular framework. This “Twitter source code” test demonstrates just that.

He literally calls it a test.

Also, I'm not saying Seniors are lone wolfs. I'm saying that they should be able to work autonomously (I.e. without supervision). I'm not prescribing what that work entails.