public async Task GetRegionUsers_returnOk() { // Arrange _regionService.Setup(x => x.GetRegionUsersAsync(It.IsAny <int>())).ReturnsAsync(new List <RegionUserDTO>()); int regionID = 1; // Act var result = await _regionController.GetRegionUsers(regionID); // Assert Assert.IsInstanceOf <OkObjectResult>(result); Assert.IsInstanceOf <List <RegionUserDTO> >((result as ObjectResult).Value); }