zzzprojects#764 Additional Tests, Missing TTL Update

Author: Travis Whidden

src/System.Linq.Dynamic.Core/Parser/ThreadSafeSlidingCache.cs

@@ -40,6 +40,7 @@ public bool TryGetValue(T1 key, out T2 value)
                 if (DateTime.UtcNow <= valueAndExpiration.ExpirationTime)
                 {
                     value = valueAndExpiration.Value;
+                    _cache[key] = (value, DateTime.UtcNow.Add(_timeToLive));
                     return true;
                 }
                 else

test/System.Linq.Dynamic.Core.Tests/Util/ConstantExpressionHelperTests.cs

@@ -16,11 +16,26 @@ public async Task TestConstantExpressionLeak()
 
             var expressions = ConstantExpressionHelper.Expressions;
 
+            // Should contain
             if (!expressions.TryGetValue(2000, out _))
             {
                 Assert.Fail("Cache was missing constant expression for 2000");
             }
-            
+
+            // wait half the expiry time
+            await Task.Delay(TimeSpan.FromSeconds(ConstantExpressionHelper.Expressions.TimeToLive.TotalSeconds/2));
+            if (!expressions.TryGetValue(2000, out _))
+            {
+                Assert.Fail("Cache was missing constant expression for 2000 (1)");
+            }
+
+            // wait another half the expiry time, plus one second
+            await Task.Delay(TimeSpan.FromSeconds((ConstantExpressionHelper.Expressions.TimeToLive.TotalSeconds / 2)+1));
+            if (!expressions.TryGetValue(2000, out _))
+            {
+                Assert.Fail("Cache was missing constant expression for 2000 (2)");
+            }
+
             // Wait for the slide cache to expire, check on second later
             await Task.Delay(ConstantExpressionHelper.Expressions.TimeToLive.Add(TimeSpan.FromSeconds(1)));