/**
 * The `node:test` module provides a standalone testing module.
 * @see [source](https://github.com/nodejs/node/blob/v18.0.0/lib/test.js)
 */
declare module 'node:test' {
  /**
   * The `test()` function is the value imported from the test module. Each invocation of this
   * function results in the creation of a test point in the TAP output.
   *
   * The {@link TestContext} object passed to the fn argument can be used to perform actions
   * related to the current test. Examples include skipping the test, adding additional TAP
   * diagnostic information, or creating subtests.
   *
   * `test()` returns a {@link Promise} that resolves once the test completes. The return value
   * can usually be discarded for top level tests. However, the return value from subtests should
   * be used to prevent the parent test from finishing first and cancelling the subtest as shown
   * in the following example.
   *
   * ```js
   * test('top level test', async (t) => {
   *   // The setTimeout() in the following subtest would cause it to outlive its
   *   // parent test if 'await' is removed on the next line. Once the parent test
   *   // completes, it will cancel any outstanding subtests.
   *   await t.test('longer running subtest', async (t) => {
   *     return new Promise((resolve, reject) => {
   *       setTimeout(resolve, 1000);
   *     });
   *   });
   * });
   * ```
   * @since v18.0.0
   * @param name The name of the test, which is displayed when reporting test results.
   *    Default: The `name` property of fn, or `'<anonymous>'` if `fn` does not have a name.
   * @param options Configuration options for the test
   * @param fn The function under test. This first argument to this function is a
   *    {@link TestContext} object. If the test uses callbacks, the callback function is
   *    passed as the second argument. Default: A no-op function.
   * @returns A {@link Promise} resolved with `undefined` once the test completes.
   */
  function test(name?: string, fn?: TestFn): Promise<void>;
  function test(name?: string, options?: TestOptions, fn?: TestFn): Promise<void>;
  function test(options?: TestOptions, fn?: TestFn): Promise<void>;
  function test(fn?: TestFn): Promise<void>;

  /**
   * The type of a function under test. This first argument to this function is a
   * {@link TestContext} object. If the test uses callbacks, the callback function is passed as
   * the second argument.
   */
  type TestFn = ((t: TestContext, done: (result?: any) => void) => any);

  /**
   * An instance of `TestContext` is passed to each test function in order to interact with the
   * test runner. However, the `TestContext` constructor is not exposed as part of the API.
   * @since v18.0.0
   */
  interface TestContext {
    /**
     * This function is used to write TAP diagnostics to the output. Any diagnostic information is
     * included at the end of the test's results. This function does not return a value.
     * @param message Message to be displayed as a TAP diagnostic.
     * @since v18.0.0
     */
    diagnostic(message: string): void;

    /**
     * If `shouldRunOnlyTests` is truthy, the test context will only run tests that have the `only`
     * option set. Otherwise, all tests are run. If Node.js was not started with the `--test-only`
     * command-line option, this function is a no-op.
     * @param shouldRunOnlyTests Whether or not to run `only` tests.
     * @since v18.0.0
     */
    runOnly(shouldRunOnlyTests: boolean): void;

    /**
     * This function causes the test's output to indicate the test as skipped. If `message` is
     * provided, it is included in the TAP output. Calling `skip()` does not terminate execution of
     * the test function. This function does not return a value.
     * @param message Optional skip message to be displayed in TAP output.
     * @since v18.0.0
     */
    skip(message?: string): void;

    /**
     * This function adds a `TODO` directive to the test's output. If `message` is provided, it is
     * included in the TAP output. Calling `todo()` does not terminate execution of the test
     * function. This function does not return a value.
     * @param message Optional `TODO` message to be displayed in TAP output.
     * @since v18.0.0
     */
    todo(message?: string): void;

    /**
     * This function is used to create subtests under the current test. This function behaves in
     * the same fashion as the top level {@link test} function.
     * @since v18.0.0
     * @param name The name of the test, which is displayed when reporting test results.
     *    Default: The `name` property of fn, or `'<anonymous>'` if `fn` does not have a name.
     * @param options Configuration options for the test
     * @param fn The function under test. This first argument to this function is a
     *    {@link TestContext} object. If the test uses callbacks, the callback function is
     *    passed as the second argument. Default: A no-op function.
     * @returns A {@link Promise} resolved with `undefined` once the test completes.
     */
    test: typeof test;
  }

  interface TestOptions {
    /**
     * The number of tests that can be run at the same time. If unspecified, subtests inherit this
     * value from their parent.
     * @default 1
     */
    concurrency?: number;

    /**
     * If truthy, and the test context is configured to run `only` tests, then this test will be
     * run. Otherwise, the test is skipped.
     * @default false
     */
    only?: boolean;

    /**
     * If truthy, the test is skipped. If a string is provided, that string is displayed in the
     * test results as the reason for skipping the test.
     * @default false
     */
    skip?: boolean | string;

    /**
     * If truthy, the test marked as `TODO`. If a string is provided, that string is displayed in
     * the test results as the reason why the test is `TODO`.
     * @default false
     */
    todo?: boolean | string;
  }

  export {
    test as default,
    test,
  };
}