add asp memory cache

test/Ocelot.UnitTests/Cache/AspMemoryCacheTests.cs

@@ -0,0 +1,83 @@
+using Microsoft.Extensions.Caching.Memory;
+
+namespace Ocelot.UnitTests.Cache
+{
+    using Ocelot.Cache;
+    using Shouldly;
+    using System;
+    using System.Threading;
+    using Xunit;
+
+    public class AspMemoryCacheTests
+    {
+        private readonly AspMemoryCache<Fake> _cache;
+
+        public AspMemoryCacheTests()
+        {
+            _cache = new AspMemoryCache<Fake>(new MemoryCache(new MemoryCacheOptions()));
+        }
+
+        [Fact]
+        public void should_cache()
+        {
+            var fake = new Fake(1);
+            _cache.Add("1", fake, TimeSpan.FromSeconds(100), "region");
+            var result = _cache.Get("1", "region");
+            result.ShouldBe(fake);
+            fake.Value.ShouldBe(1);
+        }
+
+        [Fact]
+        public void should_add_and_delete()
+        {
+            var fake = new Fake(1);
+            _cache.Add("1", fake, TimeSpan.FromSeconds(100), "region");
+            var newFake = new Fake(1);
+            _cache.AddAndDelete("1", newFake, TimeSpan.FromSeconds(100), "region");
+            var result = _cache.Get("1", "region");
+            result.ShouldBe(newFake);
+            newFake.Value.ShouldBe(1);
+        }
+
+        [Fact]
+        public void should_clear_region()
+        {
+            var fake = new Fake(1);
+            _cache.Add("1", fake, TimeSpan.FromSeconds(100), "region");
+            _cache.ClearRegion("region");
+            var result = _cache.Get("1", "region");
+            result.ShouldBeNull();
+        }
+
+        [Fact]
+        public void should_clear_key_if_ttl_expired()
+        {
+            var fake = new Fake(1);
+            _cache.Add("1", fake, TimeSpan.FromMilliseconds(50), "region");
+            Thread.Sleep(200);
+            var result = _cache.Get("1", "region");
+            result.ShouldBeNull();
+        }
+
+        [Theory]
+        [InlineData(0)]
+        [InlineData(-1)]
+        public void should_not_add_to_cache_if_timespan_empty(int ttl)
+        {
+            var fake = new Fake(1);
+            _cache.Add("1", fake, TimeSpan.FromSeconds(ttl), "region");
+            var result = _cache.Get("1", "region");
+            result.ShouldBeNull();
+        }
+
+        private class Fake
+        {
+            public Fake(int value)
+            {
+                Value = value;
+            }
+
+            public int Value { get; }
+        }
+    }
+}