public void Contains ()
{
X509CertificateCollection c = new X509CertificateCollection ();
Assert.IsTrue (!c.Contains (x509a), "Empty-A");
Assert.IsTrue (!c.Contains (null), "Empty-Null");
c.Add (x509a);
Assert.IsTrue (c.Contains (x509a), "A-A");
Assert.IsTrue (!c.Contains (x509b), "A-B");
// works by value not by object reference
X509Certificate x = new X509Certificate (cert_a);
Assert.IsTrue (c.Contains (x), "A-x");
}