At my previous company, I was the hiring manager and gave a homework assignment that was targeted a little shorter than you describe, at right about 2-3 hours. I was clear upfront that it would take about that long, though if you wanted to take longer, you could. Within reason, I didn't hold the time against the person if they took longer.
The crazy thing was that over half of the applicants that passed a resume screen and phone interview could not complete the homework assignment. Over half. Some couldn't get it at all (either gave up or had compile errors), some got it to run but it didn't work, a few got it to mostly work but their programs had serious bugs, and the last few actually got it right.
The assignment was to read a file containing a list of numbers (some formatted incorrectly, so there was some very simple parsing logic involved), call an API using each correctly formatted number as a parameter, and store what the API returned to a file.
I'm still shocked over half of developers couldn't accomplish that task. Makes me wonder what they were accomplishing in their existing roles.
The crazy thing was that over half of the applicants that passed a resume screen and phone interview could not complete the homework assignment. Over half. Some couldn't get it at all (either gave up or had compile errors), some got it to run but it didn't work, a few got it to mostly work but their programs had serious bugs, and the last few actually got it right.
The assignment was to read a file containing a list of numbers (some formatted incorrectly, so there was some very simple parsing logic involved), call an API using each correctly formatted number as a parameter, and store what the API returned to a file.
I'm still shocked over half of developers couldn't accomplish that task. Makes me wonder what they were accomplishing in their existing roles.