public void GetDuidFromDevice_DeviceFound(Boolean devicesAddedLater) { Random random = new Random(); Guid id = random.NextGuid(); UUIDDUID duid = new UUIDDUID(random.NextGuid()); Device device = new Device { Id = id, DUID = duid }; var service = new InMemoryDeviceService(devicesAddedLater == true ? null : new[] { device }); if (devicesAddedLater == true) { service.AddDevices(new[] { device }); } var actual = service.GetDuidFromDevice(id); Assert.IsAssignableFrom <UUIDDUID>(actual); Assert.Equal(duid, (UUIDDUID)actual); }