add a test for valuetask source

Author: VSadov

src/tests/async/valuetask Source/valuetaskSource.cs

@@ -0,0 +1,109 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System;
+using System.Runtime.CompilerServices;
+using System.Threading;
+using System.Threading.Tasks;
+using System.Threading.Tasks.Sources;
+using Xunit;
+
+public class Async2ValueTaskSource
+{
+    static string trace;
+
+    [Fact]
+    static void TestEntry()
+    {
+        ValueTask vtUseContext = new ValueTask(new Source(true), 1);
+
+        AwaitConfigDefault(vtUseContext).GetAwaiter().GetResult();
+        Assert.Equal("UseSchedulingContext", trace);
+        AwaitConfigTrue(vtUseContext).GetAwaiter().GetResult();
+        Assert.Equal("UseSchedulingContext", trace);
+        AwaitConfigFalse(vtUseContext).GetAwaiter().GetResult();
+        Assert.Equal("None", trace);
+
+        ValueTask vtIgnoreContext = new ValueTask(new Source(true), 1);
+        AwaitConfigDefault(vtIgnoreContext).GetAwaiter().GetResult();
+        Assert.Equal("UseSchedulingContext", trace);
+        AwaitConfigTrue(vtIgnoreContext).GetAwaiter().GetResult();
+        Assert.Equal("UseSchedulingContext", trace);
+        AwaitConfigFalse(vtIgnoreContext).GetAwaiter().GetResult();
+        Assert.Equal("None", trace);
+
+        Console.WriteLine();
+        SynchronizationContext.SetSynchronizationContext(new SideeffectingContext());
+
+        AwaitConfigDefault(vtUseContext).GetAwaiter().GetResult();
+        Assert.Equal("UseSchedulingContext Posted", trace);
+        AwaitConfigTrue(vtUseContext).GetAwaiter().GetResult();
+        Assert.Equal("UseSchedulingContext Posted", trace);
+        AwaitConfigFalse(vtUseContext).GetAwaiter().GetResult();
+        Assert.Equal("None Posted", trace);
+
+        AwaitConfigDefault(vtIgnoreContext).GetAwaiter().GetResult();
+        Assert.Equal("UseSchedulingContext Posted", trace);
+        AwaitConfigTrue(vtIgnoreContext).GetAwaiter().GetResult();
+        Assert.Equal("UseSchedulingContext Posted", trace);
+        AwaitConfigFalse(vtIgnoreContext).GetAwaiter().GetResult();
+        Assert.Equal("None Posted", trace);
+    }
+
+    class SideeffectingContext : SynchronizationContext
+    {
+        public override void Post(SendOrPostCallback d, object? state)
+        {
+            trace += " Posted";
+            base.Post(d, state);
+        }
+    }
+
+    static async ValueTask AwaitConfigDefault(ValueTask vt)
+    {
+        await (vt);
+    }
+
+    static async ValueTask AwaitConfigTrue(ValueTask vt)
+    {
+        await (vt).ConfigureAwait(true);
+    }
+
+    static async ValueTask AwaitConfigFalse(ValueTask vt)
+    {
+        await (vt).ConfigureAwait(false);
+    }
+
+    class Source : IValueTaskSource
+    {
+        private readonly bool _useContext;
+        public Source(bool useContext)
+        {
+            _useContext = useContext;
+        }
+
+        public void GetResult(short token)
+        {
+        }
+
+        public ValueTaskSourceStatus GetStatus(short token)
+        {
+            return ValueTaskSourceStatus.Pending;
+        }
+
+        public void OnCompleted(Action<object?> continuation, object? state, short token, ValueTaskSourceOnCompletedFlags flags)
+        {
+            trace = flags.ToString();
+
+            var schedulingContext = SynchronizationContext.Current;
+            if (_useContext && schedulingContext != null)
+            {
+                schedulingContext.Post((obj) => continuation(obj), state);
+            }
+            else
+            {
+                ThreadPool.QueueUserWorkItem((obj) => continuation(obj), state);
+            }
+        }
+    }
+}

src/tests/async/valuetask Source/valuetaskSource.csproj

@@ -0,0 +1,8 @@
+<Project Sdk="Microsoft.NET.Sdk.IL">
+  <PropertyGroup>
+    <Optimize>True</Optimize>
+  </PropertyGroup>
+  <ItemGroup>
+    <Compile Include="$(MSBuildProjectName).cs" />
+  </ItemGroup>
+</Project>