[Feature] support for `(it|test|describe).each(...)`

Jest supports it.each: https://jestjs.io/docs/api#testeachtablename-fn-timeout with an array or a template table.

[kirillgroshkov]

15 minutes after writing last comment, managed to “money-patch” the missing test.each support by using this quick&dirty function (and my tests pass now 🚀 )

export function testEach(cases: any[][]): (name: string, fn: AnyFunction) => void {
  return (name, fn) => {
    cases.forEach(items => {
      test(name, () => fn(...items))
    })
  }
}

[patak-dev]

This was also requested by @userquin in the EPIC issue. We were talking with Anthony that .each could add a lot of complexity (https://github.com/antfu-sponsors/vitest/issues/15#issuecomment-991333131). But given that the output is formatted as a table and people seem to be keen on using it, I think it would be good to have a compat story here. See also comment in twitter about .concurrent.each that is an interesting case (we could do the same with a nested describe.concurrent though)

What I told to @userquin, and maybe someone else wants to take this one, is that 1. it may be good to wait until the internals are more stable to avoid the need to refactor this feature while the code is stabilizing and 2. we could discuss with a PR implementing it, because maybe the added complexity isn’t that big at the end.

In case we don’t want to support tabular output in the reporter, maybe we could implement .each with nested describes and keep a simple tree output, but at least users could migrate from Jest without changing their code (but taking the hit of losing the table at the CLI)