Basic template support for Jest + VSCode, type-check tests

[sramam]

Current Behavior

I am using tsdx to setup a headless monorepo, meaning I use the basic template. Very useful. So thank you.

However, to get VSCode + jest to work correctly on the test files, I keep having to make this adjustment to tsconfig.json

Expected behavior

My needs don't seem special and I'd suspect these should be the defaults in the template.

[agilgur5]

This is effectively a duplicate of #871 and I've documented that one extensively, so I'll leave most of the details to it.

Some issues with your set-up that you may have later discovered:

• include: test can't be added there as it will make it so your tests are also compiled. Other than that being unnecessary, it could also affect directory structure etc. In tsconfig.json is not applied in test folder in VSCode #871 (comment), I recommend using a tsconfig.build.json to get around this -- one tsconfig for type-checking all your files, one for building specific files.
• types: you may be misunderstanding how tsconfig's types field works. this will make it ignore all @types libraries except for @types/jest, which I don't think you mean to do. I recommend using @jest/globals (or jest-without-globals for older versions of Jest) to avoid globals entirely, but if you are using globals, TSDX already comes installed with @types/jest, which TypeScript will automatically detect and use in your node_modules so long as your typeRoots and types haven't been configured otherwise
• rootDir: see the comment in the tsconfig.json as well as tsconfig.json is not applied in test folder in VSCode #871 (comment) 's various links