docs: function toHaveMiddleware(middleware) {
      
      expect(this.actual).toExist('Route is undefined');
      toBeAnExpressRoute(this.actual.route);
      expect(this.actual.route.stack.length).toBeGreaterThan(1, 'No middleware found');
      if(expressGuards.isMiddleware(middleware)) {
          expect(this.actual.route.stack.find(l => l.handle.toString() === middleware.toString())).toExist(`middleware is not defined`);
      } else {
          const name = middleware || '<anonymous>';
          expect(this.actual.route.stack.find(l => l.name === name)).toExist(`${name} is not defined`);
      }
  }