feat: introduce the new reporter API

[sheremet-va]

Description

Initial draft (decided to not implement onError for now):

Details

interface Reporter {
  /**
   * This method is called when the error happens outside of the test.
   *
   * Possible errors:
   * - unhandled error thrown during the test run
   * - error thrown during collection phase when importing a module (global throw)
   * - error thrown during collection phase when calling `describe` callback
   * - error thrown inside `beforeAll`/`afterAll` hooks since it can't be attributed to a specific test
   */
  onError(error: SerialisedError, suite?: TestSuite): void

  /**
   * This method is called when all tests inside a single file were collected.
   * The `file` object contains `children()` method with all suites and tests.
   * Tasks won't have `result` property yet.
   *
   * **Note:** This method can be called in parallel if multiple files are collected at the same time (`--single-worker` is used)
   */
  onFileCollected(file: TestModule): void

  /**
   * This method is called when the runner is ready to start running a test. The `result` will always be `undefined`.
   * **Note:** If test is marked as `todo` or `skip`, this method will still be called.
   */
  onTestPrepare(test: TestCase): void
  /**
   * This method is called when the test finished running. It will always have a `result` property.
   */
  onTestFinished(test: TestCase): void
  /**
   * This method is called only after the test has finished running and the `result.type` is `failed`.
   */
  onTestFailed(test: TestCase): void

  /**
   * This method is called when user logs something to the console.
   * The order of logs is not guaranteed.
   */
  onConsoleLog(type: 'stderr' | 'stdout', log: UserConsoleLog): void

  /**
   * This is called when all tests have finished running.
   */
  onTestRunFinished(files: TestModule[], errors: SerialisedError[], reason: 'passed' | 'failed' | 'timedout' | 'interrupted'): void

  /**
   * Coverage is performed for all files that were executed.
   * This is called only if `--coverage` flag is used.
   */
  onCoverage(summary: any): void
}

The current lifecycle ("run tests" has its own lifecycle):

Please don't delete this checklist! Before submitting the PR, please make sure you do the following:

• It's really useful if your PR references an issue where it is discussed ahead of time. If the feature is substantial or introduces breaking changes without a discussion, PR might be closed.
• Ideally, include a test that fails without this PR but passes with it.
• Please, don't make changes to pnpm-lock.yaml unless you introduce a new test example.

Tests

• Run the tests with pnpm test:ci.

Documentation

• If you introduce new functionality, document it. You can run documentation with pnpm run docs command.

Changesets

• Changes in changelog are generated from PR name. Please, make sure that it explains your changes in an understandable manner. Please, prefix changeset messages with feat:, fix:, perf:, docs:, or chore:.

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