Im trying to unit test some middleware.

export const someMiddleware = catchAsync(async (req: Request, res: Response, next: NextFunction) => {
//...
}

But it always returns undefined because of catchAsync

export const catchAsync = (fn: any) => {
  return function (req: Request, res: Response, next: NextFunction) {
    fn(req, res, next).catch(next);
  };
};

describe('some middleware test', () => {
  let mockRequest: Partial<Request>;
  let mockResponse: Partial<Response>;
  let nextFunction: NextFunction = jest.fn();

  beforeEach(() => {
    mockRequest = {};
    mockResponse = {
      json: jest.fn(),
    };
  });

  test('this some throw error', async () => {
    const result = await someMiddleware(mockRequest as Request, mockResponse as Response, nextFunction);
    expect(result).toEqual('...');
  });
});

So, what I'm missing or a keyword to resolve catchAsync?