Add TestReferenceCountingContainer

tests/Tgstation.Server.Host.Tests/Utils/TestReferenceCountingContainer.cs

@@ -0,0 +1,56 @@
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+
+namespace Tgstation.Server.Host.Utils.Tests
+{
+	[TestClass]
+	public sealed class TestReferenceCountingContainer
+	{
+		interface IInterface
+		{
+		}
+
+		sealed class Implementation : IInterface
+		{
+		}
+
+		sealed class Lock : ReferenceCounter<IInterface>
+		{
+			public IInterface PubInstance => Instance;
+		}
+
+
+		[TestMethod]
+		public void TestReferenceCounting()
+		{
+			var impl = new Implementation();
+			var container = new ReferenceCountingContainer<IInterface, Lock>(impl);
+
+			Assert.IsTrue(container.OnZeroReferences.IsCompleted);
+
+			var ref1 = container.AddReference();
+
+			Assert.AreSame(ref1.PubInstance, impl);
+
+			var task = container.OnZeroReferences;
+
+			Assert.AreSame(task, container.OnZeroReferences);
+			Assert.IsFalse(task.IsCompleted);
+
+			ref1.Dispose();
+
+			Assert.IsTrue(task.IsCompleted);
+			Assert.IsTrue(container.OnZeroReferences.IsCompleted);
+
+			ref1.Dispose();
+			Assert.IsTrue(container.OnZeroReferences.IsCompleted);
+
+			var ref2 = container.AddReference();
+			Assert.IsFalse((task = container.OnZeroReferences).IsCompleted);
+
+
+			ref2.Dispose();
+			Assert.IsTrue(task.IsCompleted);
+			Assert.IsTrue(container.OnZeroReferences.IsCompleted);
+		}
+	}
+}