public async Task Delete_ReturnsNull() { // arrange var guest = new Guest { guestId = 123, name = "Guest1", email = "*****@*****.**", isGoing = true, eventId = 1 }; _guestQueryMock.Setup(x => x.GetByGuestId(It.IsAny <int>())) .Returns(Task.Factory.StartNew(() => guest)); _guestQueryMock.Setup(x => x.DeleteByGuestId(It.IsAny <int>())) .Returns(Task.Factory.StartNew(() => true)); // act var task = await _sut.DeleteByGuestId(0); // assert Assert.IsType <OkObjectResult>(task); var result = task as OkObjectResult; var guestResult = result.Value as bool?; Assert.True(guestResult); }