Error output not sufficient

[Beiri22]

Describe the bug

I am using sveltekit and came upon a problem when testing. I am testing a function that uses sveltekit's error() function to create an HTTPError. When this error occurs unexpectedly inside my tests, vitest only reports "Unknown Error: undefined", which does not help finding the issue. The HttpError itself contains useful information like status code and message:

HttpError {
  status: 401,
  body: {
    message: 'Some description'
  }
}

I'm not sure why, but maybe you check on that for a correct and useful error output.

Reproduction

https://stackblitz.com/edit/sveltejs-kit-template-default-j4trhh?file=src/lookhere.test.ts

import { error } from '@sveltejs/kit';

test("Some Test",()=>{
    throw error(401, "Some message");
})

System Info

System:
    OS: Linux 6.2 Manjaro Linux
    CPU: (16) x64 Intel(R) Core(TM) i9-9900K CPU @ 3.60GHz
    Memory: 25.37 GB / 31.27 GB
    Container: Yes
    Shell: 3.6.0 - /usr/bin/fish
  Binaries:
    Node: 19.5.0 - /usr/bin/node
    Yarn: 1.22.19 - /usr/bin/yarn
    npm: 8.19.2 - /usr/bin/npm
  Browsers:
    Chromium: 109.0.5414.119
    Firefox: 109.0
  npmPackages:
    vite: ^4.0.0 => 4.0.4 
    vitest: ^0 => 0.28.3

Used Package Manager

npm

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• The provided reproduction is a minimal reproducible example of the bug.