[Debugreality]

As a hiring manager the test that I believe works best is a code reading exercise. This helps reduce anxiety or the effects of anxiety (fear has a very big negative effect on creative thinking)

I take a small fairly self contained function from the existing code base. Give them 10 minutes to read the function.

You can also add a few actual bugs into the function if you like to see if they are picked up.

I then generally ask them a couple of questions. First to step through what the function is doing. Then what the larger context of the function might be and finally if they have any thoughts on improving the function.

It's a quick test usually under 20 minutes you can even hand it over to non technical interviewers if you describe what kind of answers they should be looking for.