chore: import upstream snapshot with attribution

dotnet/tests/Microsoft.Agents.AI.Hosting.UnitTests/SessionIsolationKeyProviderTests.cs

@@ -0,0 +1,95 @@
+// Copyright (c) Microsoft. All rights reserved.
+
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace Microsoft.Agents.AI.Hosting.UnitTests;
+
+/// <summary>
+/// Unit tests for <see cref="SessionIsolationKeyProvider"/> and its contract.
+/// </summary>
+public class SessionIsolationKeyProviderTests
+{
+    /// <summary>
+    /// Verify that a concrete provider can return a non-null isolation key.
+    /// </summary>
+    [Fact]
+    public async Task GetSessionIsolationKeyAsyncReturnsNonNullKeyAsync()
+    {
+        // Arrange
+        const string ExpectedKey = "test-key";
+        var provider = new TestSessionIsolationKeyProvider(ExpectedKey);
+
+        // Act
+        string? result = await provider.GetSessionIsolationKeyAsync();
+
+        // Assert
+        Assert.Equal(ExpectedKey, result);
+    }
+
+    /// <summary>
+    /// Verify that a concrete provider can return null when no key is available.
+    /// </summary>
+    [Fact]
+    public async Task GetSessionIsolationKeyAsyncReturnsNullWhenNoKeyAvailableAsync()
+    {
+        // Arrange
+        var provider = new TestSessionIsolationKeyProvider(null);
+
+        // Act
+        string? result = await provider.GetSessionIsolationKeyAsync();
+
+        // Assert
+        Assert.Null(result);
+    }
+
+    /// <summary>
+    /// Verify that cancellation token is passed through to the provider implementation.
+    /// </summary>
+    [Fact]
+    public async Task GetSessionIsolationKeyAsyncPassesCancellationTokenAsync()
+    {
+        // Arrange
+        var provider = new TestCancellableSessionIsolationKeyProvider();
+        using var cts = new CancellationTokenSource();
+        cts.Cancel();
+
+        // Act & Assert
+        await Assert.ThrowsAsync<TaskCanceledException>(
+            async () => await provider.GetSessionIsolationKeyAsync(cts.Token));
+    }
+
+    #region Test Implementations
+
+    /// <summary>
+    /// Test implementation of <see cref="SessionIsolationKeyProvider"/> for testing purposes.
+    /// </summary>
+    private sealed class TestSessionIsolationKeyProvider : SessionIsolationKeyProvider
+    {
+        private readonly string? _key;
+
+        public TestSessionIsolationKeyProvider(string? key)
+        {
+            this._key = key;
+        }
+
+        public override ValueTask<string?> GetSessionIsolationKeyAsync(CancellationToken cancellationToken = default)
+        {
+            return new ValueTask<string?>(this._key);
+        }
+    }
+
+    /// <summary>
+    /// Test implementation that respects cancellation tokens.
+    /// </summary>
+    private sealed class TestCancellableSessionIsolationKeyProvider : SessionIsolationKeyProvider
+    {
+        public override async ValueTask<string?> GetSessionIsolationKeyAsync(CancellationToken cancellationToken = default)
+        {
+            await Task.Delay(1000, cancellationToken);
+            return "key";
+        }
+    }
+
+    #endregion
+}