Expected behavior: `expect(() => { throw undefined }).toThrow('Input validation failed')` should fail.

Describe the bug

Encountered unexpected behavior where throwing undefined still passed the tests. This occurred because I created a mock function meant to check the error before throwing, but I forgot to implement the check.

Expected behavior: expect(() => { throw undefined }).toThrow('Input validation failed') should fail.

Reproduction

Expected behavior: expect(() => { throw undefined }).toThrow('Input validation failed') should fail.

System Info

System:
    OS: Linux 6.8 Ubuntu 24.04.1 LTS 24.04.1 LTS (Noble Numbat)
    CPU: (8) x64 Intel(R) Core(TM) i5-8265U CPU @ 1.60GHz
    Memory: 2.06 GB / 7.57 GB
    Container: Yes
    Shell: 5.9 - /usr/bin/zsh
  Binaries:
    Node: 22.12.0 - ~/.nvm/versions/node/v22.12.0/bin/node
    npm: 10.9.0 - ~/.nvm/versions/node/v22.12.0/bin/npm
    pnpm: 9.15.2 - ~/.nvm/versions/node/v22.12.0/bin/pnpm
  Browsers:
    Chrome: 131.0.6778.264
  npmPackages:
    @vitest/coverage-v8: ^2.1.1 => 2.1.8 
    vitest: ^2.1.8 => 2.1.8

Used Package Manager

pnpm

Validations

• Follow our Code of Conduct
• Read the Contributing Guidelines.
• Read the docs.
• Check that there isn't already an issue that reports the same bug to avoid creating a duplicate.
• Check that this is a concrete bug. For Q&A open a GitHub Discussion or join our Discord Chat Server.
• The provided reproduction is a minimal reproducible example of the bug.

Start by reproducing the provided toThrow expectation with the repository's test runner, then locate the implementation and existing tests for toThrow. Add a regression test covering throw undefined with a non-empty expected message, and consider the issue complete when that expectation fails as described while existing matcher tests still pass.