Concrete AsyncAccessSerializer impl and basline tests

1 files changed, 90 insertions, 0 deletions

diff --git a/lib/Utils/tests/Async/AsyncAccessSerializerTests.cs b/lib/Utils/tests/Async/AsyncAccessSerializerTests.cs
new file mode 100644
index 0000000..5bb8b8a
--- /dev/null
+++ b/lib/Utils/tests/Async/AsyncAccessSerializerTests.cs
@@ -0,0 +1,90 @@
+
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+
+using System;
+using System.Threading;
+using System.Threading.Tasks;
+using System.Collections.Generic;
+
+namespace VNLib.Utils.Async.Tests
+{
+    [TestClass()]
+    public class AsyncAccessSerializerTests
+    {
+        [TestMethod()]
+        public void AsyncAccessSerializerTest()
+        {
+            /*
+             * Very basic single threaded test to confrim
+             * async serialzation of a given resource
+             */
+
+            const string DEFAULT_KEY = "default";
+
+            //Alloc serailzer base on string 
+            IAsyncAccessSerializer<string> serializer = new AsyncAccessSerializer<string>(100, 100, StringComparer.Ordinal);
+
+            Task first = serializer.WaitAsync(DEFAULT_KEY);
+
+            //The first call to wait should complete synchronously
+            Assert.IsTrue(first.IsCompleted);
+
+            //Second call to wait should yeild async
+            Task second = serializer.WaitAsync(DEFAULT_KEY);
+            Assert.IsFalse(second.IsCompleted);
+
+            //Create a 3rd call to wait
+            Task third = serializer.WaitAsync(DEFAULT_KEY);
+            Assert.IsFalse(third.IsCompleted);
+
+            //Release one call
+            serializer.Release(DEFAULT_KEY);
+
+            //Second call can be called sync
+            second.GetAwaiter().GetResult();
+
+            //Third call should still be waiting
+            Assert.IsFalse(third.IsCompleted);
+
+            //Second release
+            serializer.Release(DEFAULT_KEY);
+            third.GetAwaiter().GetResult();
+
+            //Third/final release
+            serializer.Release(DEFAULT_KEY);
+
+            //Confirm an excess release raises exception
+            Assert.ThrowsException<KeyNotFoundException>(() => serializer.Release(DEFAULT_KEY));
+        }
+
+        /*
+         * Tests the async cancellation feature of the async
+         * wait.
+         */
+        [TestMethod()]
+        public void AsyncAccessSerializerCancellationTest()
+        {
+            const string DEFAULT_KEY = "default";
+
+            //Alloc serailzer base on string 
+            IAsyncAccessSerializer<string> serializer = new AsyncAccessSerializer<string>(100, 100, StringComparer.Ordinal);
+
+            //Enter the wait one time and dont release it
+            _ = serializer.WaitAsync(DEFAULT_KEY);
+
+            using CancellationTokenSource cts = new();
+
+            //try to enter again
+            Task reentry = serializer.WaitAsync(DEFAULT_KEY, cts.Token);
+
+            //confirm an async await is requested
+            Assert.IsFalse(reentry.IsCompleted);
+
+            //Cancel the cts and confirm cancelled result
+            cts.Cancel();
+
+            //Confirm the task raises cancellation
+            Assert.ThrowsException<OperationCanceledException>(() => reentry.GetAwaiter().GetResult());
+        }
+    }
+}
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