public void AddThenGet(string addUriString, string getUriString, bool expected)
        {
            var contentCache = new ContentCache();
            var addUri       = new Uri(addUriString, UriKind.RelativeOrAbsolute);

            contentCache.AddOrUpdate(addUri, 1);
            object value;
            var    getUri = new Uri(getUriString, UriKind.RelativeOrAbsolute);

            Assert.AreEqual(expected, contentCache.TryGetValue(getUri, out value));
            if (expected)
            {
                Assert.AreEqual(1, value);
            }
            else
            {
                Assert.IsNull(value);
            }
        }