public async Task GetMembers_ReturnsOkObjectResult() { // Arrange int id = 2; _regionService.Setup(x => x.GetMembersAsync(It.IsAny <int>())).ReturnsAsync(new List <CityDTO>()); // Act var result = await _regionController.GetMembers(id); var actual = (result as ObjectResult).Value; // Assert Assert.IsInstanceOf <OkObjectResult>(result); Assert.IsInstanceOf <IEnumerable <CityDTO> >(actual); }