public void TestThatPassingInNullForTheUriReturnsEmptyStringForEachElement()
        {
            string sSipURI           = null;
            string sExpectedUsername = "";
            string sExpectedDomain   = "";
            string sExpectedPort     = "";

            Assert.That(m_sipFormatter.GetUsernameFromUri(sSipURI), Is.EqualTo(sExpectedUsername));
            Assert.That(m_sipFormatter.GetDomainFromUri(sSipURI), Is.EqualTo(sExpectedDomain));
            Assert.That(m_sipFormatter.GetPortFromUri(sSipURI), Is.EqualTo(sExpectedPort));
        }