Per-directory coverage thresholds

[lcswillems]

Clear and concise description of the problem

I cannot set coverage thresholds globally and also for a specific directory.

Suggested solution

Something similar to coverageThreshold of Jest: https://jestjs.io/docs/configuration#coveragethreshold-object

Alternative

No response

Additional context

No response

Validations

• Follow our Code of Conduct
• Read the Contributing Guidelines.
• Read the docs.
• Check that there isn't already an issue that request the same feature to avoid creating a duplicate.

[AriPerkkio]

Now that @vitest/coverage-c8 is being deprecated, we can implement this for both coverage providers. I think it would be breaking change though, as option structure would change.

[adriengibrat]

I think it would be breaking change though, as option structure would change.

does not have to introduce Breaking change, "coverageThreshold" could be an alternative property like it is implemented in jest.

[AriPerkkio]

The current option format would be replaced with new one.

These options:

{
  test: {
    coverage: {
      branches: 100,
      lines: 100,
      statements: 100,
      functions: 100,
    }
  }
}

would be replaced with these ones:

{
  test: {
    coverage: {
      threshold: {
        global {
          branches: 100,
          lines: 100,
          statements: 100,
          functions: 100,
        },
        "./src/utils/**": {
          lines: 80,
        }
      }
    }
  }
}

But sure, it doesn't have to be a breaking change at first. The coverage['lines'|'branches'|'statements'|'functions'] could be used as fallback for coverage.threshold.global before they are completely removed from configuration API.