public async Task GetBriefListSeasons_WhenCalled_ReturnSeasonsFromDb() { var expectedSeasons = new List <Season>() { new Season { Id = 1 }, new Season { Id = 2 }, new Season { Id = 3 }, }; _seasonService.Setup(s => s.GetBriefListAsync()).ReturnsAsync(expectedSeasons); var result = await _seasonsController.GetBriefListSeasons(); var okObjectResult = result as OkObjectResult; var okObjectResultValue = okObjectResult.Value as IEnumerable <SeasonBriefListDto>; Assert.That(result, Is.TypeOf <OkObjectResult>()); Assert.That(okObjectResultValue, Is.Not.Null); Assert.That(okObjectResultValue.Count(), Is.EqualTo(3)); }