public async void DownloadTwinJsonTest()
{
var deviceId = _fixture.Create <string>();
var deviceModel = _fixture.Create <DeviceModel>();
deviceModel.Twin = _fixture.Create <Microsoft.Azure.Devices.Shared.Twin>();
_deviceLogicMock.Setup(mock => mock.GetDeviceAsync(deviceId)).ReturnsAsync(deviceModel);
var result = await _deviceController.DownloadTwinJson(deviceId);
Assert.Equal(((FileContentResult)result).FileContents, System.Text.UTF8Encoding.UTF8.GetBytes(deviceModel.Twin.ToJson()));
_deviceLogicMock.Setup(mock => mock.GetDeviceAsync(deviceId)).ReturnsAsync(null);
await Assert.ThrowsAsync <DeviceAdmin.Infrastructure.Exceptions.DeviceNotRegisteredException>(() => _deviceController.DownloadTwinJson(deviceId));
deviceId = null;
await Assert.ThrowsAsync <ArgumentException>(() => _deviceController.DownloadTwinJson(deviceId));
}