Is there an existing issue for this?

• I have searched the existing issues

Have you read the CONTRIBUTING guide on posting bugs, and CODE_OF_CONDUCT?

• yes I read the things

This issue exists in the latest tap version

• I am using the latest tap

Description

There are two issues in the src/test/scripts/build.mts that lead to being unable to generate the test class on Windows:

• The call to npm run prepare fails silently if it fails
• On platforms that do not have a literal npm available on the path (i.e. Windows, which has a npm.cmd instead), the script fails with a ENOENT, which is never shown to the user

Because a) the fail is silent and b) there is an existing test-built in the packages distributed on npm, this leads to the user being able to run tests but unable to install 3rd-party plugins.

The fixes are respectively:

• Add a check on the result of spawnSync and fail if the script if something happens
• Use cross-spawn instead of Node's spawn, or manually add a .cmd if on Windows

Reproduction

Main symptom:

• On Windows Install a plugin via your package manager, add it to your config manually
  • You can't run tap plugin add due to a separate issue ([BUG] Cannot tap plugin add on Windows #989)
• Run tap build
• Run console.log(t.pluginSignature) in a test file

Your plugin will not be there.

Environment

On Windows, latest tap