private void CachingPolicyNotFound(PolicyResolver resolver, CacheSettings cacheSettings)
        {
            var emailAddress = new MailAddress(EmailDoesNotExist);
            var source       = resolver.GetIncomingPolicy(emailAddress);
            var cached       = resolver.Cache.Get(emailAddress.Host);

            VerifyCertNotFound(source, cached, cacheSettings.NegativeCache);

            // now get it served from the cache.
            source = resolver.GetIncomingPolicy(emailAddress);
            cached = resolver.Cache.Get(emailAddress.Host);

            VerifyCertNotFound(source, cached, cacheSettings.NegativeCache);
        }
        public void CachingVerifyDisabledNullCacheSettings()
        {
            var policyIndex      = new CertPolicyIndexStub();
            var policyExpression = new KeyUsageExtensionField(false);
            var emailAddress     = new MailAddress(Email);

            policyIndex.Add(emailAddress.Host, policyExpression);

            var resolver = new PolicyResolver(policyIndex, null);
            var source   = resolver.GetIncomingPolicy(emailAddress);

            Assert.Null(resolver.Cache);
            Assert.True(source.Count > 0);
        }