public void TestAddHeader()
{
var test = new Header();
test.AddSubVal("foo", new List<string> { "a", "b" });
var mime = new MailMessage();
test.AddHeader(mime);
var result = mime.Headers.Get("x-smtpapi");
Assert.AreEqual("{\"sub\" : {\"foo\" : [\"a\", \"b\"]}}", result);
}