public void should_generate_unique_ContentId()
{
var firstContentId = new MimePart(_textfilePath, true).ContentId;
var secondContentId = new MimePart(_textfilePath, true).ContentId;
firstContentId.ShouldMatch("^<AMLv2[0-9]*@[^>]*>$");
secondContentId.ShouldMatch("^<AMLv2[0-9]*@[^>]*>$");
firstContentId.ShouldNotEqual(secondContentId);
}