public void Saml2SubjectExtensions_ToXElement_SubjectConfirmationData()
        {
            var destination = new Uri("http://sp.example.com");
            var inResponseTo = new Saml2Id("abc123");
            var notOnOrAfter = DateTime.UtcNow.AddMinutes(2);
            var notBefore = DateTime.UtcNow;

            var saml2SubjectConfirmationData = new Saml2SubjectConfirmationData
            {
                NotOnOrAfter = notOnOrAfter,
                InResponseTo = inResponseTo,
                Recipient = destination,
                NotBefore = notBefore
            };

            var confirmation = saml2SubjectConfirmationData.ToXElement();

            confirmation.Attribute("NotOnOrAfter").Value.Should().Be(notOnOrAfter.ToSaml2DateTimeString());

            confirmation.Attribute("NotBefore").Value.Should().Be(notBefore.ToSaml2DateTimeString());

            confirmation.Attribute("Recipient").Value.Should().Be(destination.OriginalString);

            confirmation.Attribute("InResponseTo").Value.Should().Be(inResponseTo.Value);
        }