I had someone do this in my C# / .NET Core / SQL coding test interview as well, I didn't just end it right there as I wanted to see if they could solve the coding test in the time frame allowed.
They did not, I now state you can search anything online but can't copy and paste from an LLM so as not to waste my time.
What did your test involve? That's my occupational stack, and I am always curious how interviews are conducted these days. I haven't applied for a job in over 9 years, if that tells you anything.