From a5f13ed2685f5916dc858dcf4c101e853d9d395d Mon Sep 17 00:00:00 2001
From: Rafael Staib <me@rafaelstaib.com>
Date: Mon, 30 Jul 2018 15:58:38 +0200
Subject: [PATCH] Added tests for sliding expiration and improved TouchEntry
 (#21)

---
 src/Core.Tests/TaskCacheTests.cs | 43 ++++++++++++++++++++++++++++++++
 src/Core/TaskCache.cs            | 12 +++++----
 2 files changed, 50 insertions(+), 5 deletions(-)

diff --git a/src/Core.Tests/TaskCacheTests.cs b/src/Core.Tests/TaskCacheTests.cs
index a806ac4..f2ed5ab 100644
--- a/src/Core.Tests/TaskCacheTests.cs
+++ b/src/Core.Tests/TaskCacheTests.cs
@@ -390,5 +390,48 @@ public async Task TryGetValueResult()
         }
 
         #endregion
+
+        #region Expiration
+
+        [Fact(DisplayName = "VerifyExpirationFalse: Should return false if expired")]
+        public async Task VerifyExpirationFalse()
+        {
+            // arrange
+            var cacheSize = 10;
+            TimeSpan slidingExpiration = TimeSpan.FromMilliseconds(200);
+            var cache = new TaskCache<string, string>(cacheSize,
+                slidingExpiration);
+            var key = "Foo";
+
+            cache.TryAdd(key, Task.FromResult("Bar"));
+            await Task.Delay(300).ConfigureAwait(false);
+
+            // act
+            var exists = cache.TryGetValue(key, out Task<string> actual);
+
+            // assert
+            Assert.False(exists);
+        }
+
+        [Fact(DisplayName = "VerifyExpirationTrue: Should return true if not expired")]
+        public void VerifyExpirationTrue()
+        {
+            // arrange
+            var cacheSize = 10;
+            TimeSpan slidingExpiration = TimeSpan.FromMilliseconds(500);
+            var cache = new TaskCache<string, string>(cacheSize,
+                slidingExpiration);
+            var key = "Foo";
+
+            cache.TryAdd(key, Task.FromResult("Bar"));
+
+            // act
+            var exists = cache.TryGetValue(key, out Task<string> actual);
+
+            // assert
+            Assert.True(exists);
+        }
+
+        #endregion
     }
 }
diff --git a/src/Core/TaskCache.cs b/src/Core/TaskCache.cs
index 861f63a..a74f48e 100644
--- a/src/Core/TaskCache.cs
+++ b/src/Core/TaskCache.cs
@@ -113,15 +113,17 @@ public bool TryGetValue(TKey key, out Task<TValue> value)
 
         private void TouchEntry(CacheEntry entry)
         {
-            _sync.Lock(
-                () => _first != entry.Rank,
-                () =>
+            lock (_sync)
+            {
+                entry.LastTouched = DateTimeOffset.UtcNow;
+
+                if (_first != entry.Rank)
                 {
-                    entry.LastTouched = DateTimeOffset.UtcNow;
                     _ranking.Remove(entry.Rank);
                     _ranking.AddFirst(entry.Rank);
                     _first = entry.Rank;
-                });
+                }
+            }
         }
 
         private void ClearSpaceForNewEntry()