public void ShouldRetrieveLinkedResource()
{
ISmtpClient smtpClient = new EmailClient();
var imageSource = $@"{AppDomain.CurrentDomain.SetupInformation.ApplicationBase}Utils\Images\govuklogo.png";
var imageId = "someid";
byte[] expectedBytes = StreamExtensions.GetBytesFromFile(imageSource);
LinkedResource resource = smtpClient.GetLinkedResource(imageSource, imageId);
byte[] actualBytes = resource.ContentStream.ReadAllBytes();
Assert.AreEqual(imageId, resource.ContentId);
Assert.AreEqual(expectedBytes, actualBytes);
}