Just my two cents, but as a candidate I much prefer the tests to a whiteboard. I've had interview tests for a majority of my recent (senior level) positions in NYC, but the questions generally aren't to this extreme, certainly not basis for a new startup level problems.
More like "we've laid out an API contract, implement these 3 endpoints in a language you like along with these few extra small requirements and some unit tests". Usually takes 2-3 hours and I think it's a more fair assessment of my work and at least I get to use my own environment and work on my own time with tools I know rather than with someone sitting over my shoulder and a marker. It also helps drive the discussion during in-person interviews away from the binary tree puzzle type questions and focuses more on design decisions and other considerations I took in to account.
More like "we've laid out an API contract, implement these 3 endpoints in a language you like along with these few extra small requirements and some unit tests". Usually takes 2-3 hours and I think it's a more fair assessment of my work and at least I get to use my own environment and work on my own time with tools I know rather than with someone sitting over my shoulder and a marker. It also helps drive the discussion during in-person interviews away from the binary tree puzzle type questions and focuses more on design decisions and other considerations I took in to account.