Function concurrentFn

packages/jest-jasmine2/src/jasmineAsyncInstall.ts:202–233

(
    specName: Global.TestNameLike,
    fn: Global.ConcurrentTestFn,
    timeout?: number,
  )

  mutex: ReturnType<typeof pLimit>,
): Global.ItConcurrentBase {
  const concurrentFn = function (
    specName: Global.TestNameLike,
    fn: Global.ConcurrentTestFn,
    timeout?: number,
  ) {
    let promise: Promise<unknown> = Promise.resolve();

    const spec = originalFn.call(env, specName, () => promise, timeout);
    if (env != null && !env.specFilter(spec)) {
      return spec;
    }

    try {
      promise = mutex(() => {
        const promise = fn();
        if (isPromise(promise)) {
          return promise;
        }
        throw new Error(
          `Jest: concurrent test "${spec.getFullName()}" must return a Promise.`,
        );
      });
    } catch (error) {
      promise = Promise.reject(error);
    }
    // Avoid triggering the uncaught promise rejection handler in case the test errors before
    // being awaited on.
    // eslint-disable-next-line @typescript-eslint/no-empty-function
    promise.catch(() => {});

    return spec;
  };

  // eslint-disable-next-line unicorn/consistent-function-scoping
  const failing = () => {