public void Add()
        {
            var cache   = new Mock <IDistributedCache>(MockBehavior.Strict);
            var service = new DistributedSignatureCache(cache.Object);

            var dt = DateTimeOffset.UtcNow;

            cache.Setup(x => x.Set("hmac:A", It.IsAny <byte[]>(), It.IsAny <DistributedCacheEntryOptions>()));

            service.Add("A", dt);
        }
        public void CacheHit()
        {
            var cache   = new Mock <IDistributedCache>(MockBehavior.Strict);
            var service = new DistributedSignatureCache(cache.Object);

            cache.Setup(x => x.Get("hmac:A")).Returns(new byte[1]);

            var candidate = service.Contains("A");

            Assert.That(candidate, Is.True, "Cache entry differs");
        }