Add unit tests for DevUIAggregatorHostedService; refactor project files for TargetFrameworks support

dotnet/aspire-integration/Aspire.Hosting.AgentFramework.DevUI/Aspire.Hosting.AgentFramework.DevUI.csproj

@@ -10,6 +10,10 @@
     <NoWarn>$(NoWarn);CA1873;RCS1061;VSTHRD002;IL2026;IL3050</NoWarn>
   </PropertyGroup>
 
+  <ItemGroup>
+    <InternalsVisibleTo Include="Aspire.Hosting.AgentFramework.DevUI.UnitTests" />
+  </ItemGroup>
+
   <ItemGroup>
     <FrameworkReference Include="Microsoft.AspNetCore.App" />
   </ItemGroup>

dotnet/aspire-integration/Aspire.Hosting.AgentFramework.DevUI/DevUIAggregatorHostedService.cs

@@ -37,9 +37,6 @@ internal sealed class DevUIAggregatorHostedService : IAsyncDisposable
     // Frontend resources loaded from the Microsoft.Agents.AI.DevUI assembly (null if unavailable)
     private readonly Dictionary<string, (string ResourceName, string ContentType)>? _frontendResources;
 
-    // Lazily resolved and cached backend map: prefix → base URL
-    private Dictionary<string, string>? _cachedBackends;
-
     public DevUIAggregatorHostedService(
         DevUIResource resource,
         ILogger logger)
@@ -279,15 +276,10 @@ internal sealed class DevUIAggregatorHostedService : IAsyncDisposable
 
     /// <summary>
     /// Resolves backend URLs from the resource's <see cref="AgentServiceAnnotation"/> annotations.
-    /// Results are cached after first successful resolution of at least one backend.
+    /// This method does not cache results to ensure late-allocated backends are always discovered.
     /// </summary>
     private Dictionary<string, string> ResolveBackends()
     {
-        if (this._cachedBackends is not null)
-        {
-            return this._cachedBackends;
-        }
-
         var result = new Dictionary<string, string>(StringComparer.Ordinal);
 
         foreach (var annotation in this._resource.Annotations.OfType<AgentServiceAnnotation>())
@@ -313,12 +305,6 @@ internal sealed class DevUIAggregatorHostedService : IAsyncDisposable
             }
         }
 
-        // Only cache if we resolved at least one backend
-        if (result.Count > 0)
-        {
-            this._cachedBackends = result;
-        }
-
         return result;
     }
 
@@ -470,13 +456,19 @@ internal sealed class DevUIAggregatorHostedService : IAsyncDisposable
     {
         // Try to determine the backend from agent_id query param or request body
         string? backendUrl = null;
+        string? actualAgentId = null;
 
         var agentId = context.Request.Query["agent_id"].FirstOrDefault();
         if (agentId is not null)
         {
-            (backendUrl, _) = this.ResolveBackend(agentId);
+            (backendUrl, actualAgentId) = this.ResolveBackend(agentId);
         }
 
+        // Build query string with rewritten agent_id if we resolved from query param
+        var queryString = (agentId is not null && actualAgentId is not null)
+            ? RewriteAgentIdInQueryString(context.Request.QueryString, actualAgentId)
+            : context.Request.QueryString.ToString();
+
         if (backendUrl is null && context.Request.ContentLength > 0)
         {
             var bodyBytes = await ReadRequestBodyAsync(context.Request).ConfigureAwait(false);
@@ -504,8 +496,14 @@ internal sealed class DevUIAggregatorHostedService : IAsyncDisposable
 
                     var rewritten = JsonSerializer.SerializeToUtf8Bytes(json);
                     var targetPath = string.IsNullOrEmpty(path) ? "/v1/conversations" : $"/v1/conversations/{path}";
+
+                    // Also rewrite query string agent_id if present
+                    var bodyQueryString = (agentId is not null)
+                        ? RewriteAgentIdInQueryString(context.Request.QueryString, actualId)
+                        : context.Request.QueryString.ToString();
+
                     await ProxyRequestAsync(
-                        context, backendUrl, targetPath + context.Request.QueryString, rewritten).ConfigureAwait(false);
+                        context, backendUrl, targetPath + bodyQueryString, rewritten).ConfigureAwait(false);
                     return;
                 }
             }
@@ -520,7 +518,7 @@ internal sealed class DevUIAggregatorHostedService : IAsyncDisposable
 
             var targetPathFallback = string.IsNullOrEmpty(path) ? "/v1/conversations" : $"/v1/conversations/{path}";
             await ProxyRequestAsync(
-                context, backendUrl, targetPathFallback + context.Request.QueryString, bodyBytes).ConfigureAwait(false);
+                context, backendUrl, targetPathFallback + queryString, bodyBytes).ConfigureAwait(false);
             return;
         }
 
@@ -534,7 +532,23 @@ internal sealed class DevUIAggregatorHostedService : IAsyncDisposable
 
         var convPath = string.IsNullOrEmpty(path) ? "/v1/conversations" : $"/v1/conversations/{path}";
         await ProxyRequestAsync(
-            context, backendUrl, convPath + context.Request.QueryString, bodyBytes: null).ConfigureAwait(false);
+            context, backendUrl, convPath + queryString, bodyBytes: null).ConfigureAwait(false);
+    }
+
+    /// <summary>
+    /// Rewrites the agent_id query parameter to the un-prefixed value for backend routing.
+    /// </summary>
+    internal static string RewriteAgentIdInQueryString(QueryString queryString, string actualAgentId)
+    {
+        if (!queryString.HasValue)
+        {
+            return string.Empty;
+        }
+
+        var query = Microsoft.AspNetCore.WebUtilities.QueryHelpers.ParseQuery(queryString.Value);
+        query["agent_id"] = actualAgentId;
+
+        return QueryString.Create(query).ToString();
     }
 
     private static async Task ProxyRequestAsync(

dotnet/aspire-integration/Aspire.Hosting.AgentFramework.DevUI/README.md

@@ -1,4 +1,4 @@
-# Aspire.Hosting.AgentFramework library
+# Aspire.Hosting.AgentFramework.DevUI library
 
 Provides extension methods and resource definitions for an Aspire AppHost to configure a DevUI resource for testing and debugging AI agents built with [Microsoft Agent Framework](https://github.com/microsoft/agent-framework).
 
@@ -10,10 +10,10 @@ Agent services must expose the OpenAI Responses and Conversations API endpoints.
 
 ### Install the package
 
-In your AppHost project, install the Aspire Agent Framework Hosting library with [NuGet](https://www.nuget.org):
+In your AppHost project, install the Aspire Agent Framework DevUI Hosting library with [NuGet](https://www.nuget.org):
 
 ```dotnetcli
-dotnet add package Aspire.Hosting.AgentFramework
+dotnet add package Aspire.Hosting.AgentFramework.DevUI
 ```
 
 ## Usage example

dotnet/samples/DevUIIntegration/DevUIIntegration.ServiceDefaults/DevUIIntegration.ServiceDefaults.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>net10.0</TargetFrameworks>
+    <TargetFramework>net10.0</TargetFramework>
     <ImplicitUsings>enable</ImplicitUsings>
     <Nullable>enable</Nullable>
     <IsAspireSharedProject>true</IsAspireSharedProject>

dotnet/samples/DevUIIntegration/EditorAgent/EditorAgent.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk.Web">
 
   <PropertyGroup>
-    <TargetFrameworks>net10.0</TargetFrameworks>
+    <TargetFramework>net10.0</TargetFramework>
     <Nullable>enable</Nullable>
     <ImplicitUsings>enable</ImplicitUsings>
     <UserSecretsId>b2c3d4e5-f6a7-8901-bcde-f12345678901</UserSecretsId>

dotnet/samples/DevUIIntegration/WriterAgent/WriterAgent.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk.Web">
 
   <PropertyGroup>
-    <TargetFrameworks>net10.0</TargetFrameworks>
+    <TargetFramework>net10.0</TargetFramework>
     <Nullable>enable</Nullable>
     <ImplicitUsings>enable</ImplicitUsings>
     <UserSecretsId>a1b2c3d4-e5f6-7890-abcd-ef1234567890</UserSecretsId>

dotnet/tests/Aspire.Hosting.AgentFramework.DevUI.UnitTests/Aspire.Hosting.AgentFramework.DevUI.UnitTests.csproj

@@ -1,9 +1,13 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFrameworks>net10.0</TargetFrameworks>
+    <TargetFrameworks>$(TargetFrameworksCore)</TargetFrameworks>
   </PropertyGroup>
 
+  <ItemGroup>
+    <FrameworkReference Include="Microsoft.AspNetCore.App" />
+  </ItemGroup>
+
   <ItemGroup>
     <PackageReference Include="Aspire.Hosting" />
   </ItemGroup>

dotnet/tests/Aspire.Hosting.AgentFramework.DevUI.UnitTests/DevUIAggregatorHostedServiceTests.cs

@@ -0,0 +1,299 @@
+// Copyright (c) Microsoft. All rights reserved.
+
+using System.Linq;
+using Aspire.Hosting;
+using Aspire.Hosting.ApplicationModel;
+using Microsoft.AspNetCore.Http;
+
+namespace Aspire.Hosting.AgentFramework.DevUI.UnitTests;
+
+/// <summary>
+/// Unit tests for the <see cref="DevUIAggregatorHostedService"/> class.
+/// </summary>
+public class DevUIAggregatorHostedServiceTests
+{
+    #region RewriteAgentIdInQueryString Tests
+
+    /// <summary>
+    /// Verifies that RewriteAgentIdInQueryString returns empty string when query string has no value.
+    /// </summary>
+    [Fact]
+    public void RewriteAgentIdInQueryString_EmptyQueryString_ReturnsEmptyString()
+    {
+        // Arrange
+        var queryString = QueryString.Empty;
+
+        // Act
+        var result = DevUIAggregatorHostedService.RewriteAgentIdInQueryString(queryString, "writer");
+
+        // Assert
+        Assert.Equal(string.Empty, result);
+    }
+
+    /// <summary>
+    /// Verifies that RewriteAgentIdInQueryString rewrites agent_id to the un-prefixed value.
+    /// </summary>
+    [Fact]
+    public void RewriteAgentIdInQueryString_WithPrefixedAgentId_RewritesToUnprefixed()
+    {
+        // Arrange
+        var queryString = new QueryString("?agent_id=writer-agent%2Fwriter");
+
+        // Act
+        var result = DevUIAggregatorHostedService.RewriteAgentIdInQueryString(queryString, "writer");
+
+        // Assert
+        Assert.Contains("agent_id=writer", result);
+        Assert.DoesNotContain("writer-agent", result);
+    }
+
+    /// <summary>
+    /// Verifies that RewriteAgentIdInQueryString preserves other query parameters.
+    /// </summary>
+    [Fact]
+    public void RewriteAgentIdInQueryString_WithOtherParams_PreservesOtherParams()
+    {
+        // Arrange
+        var queryString = new QueryString("?agent_id=writer-agent%2Fwriter&conversation_id=123&page=5");
+
+        // Act
+        var result = DevUIAggregatorHostedService.RewriteAgentIdInQueryString(queryString, "writer");
+
+        // Assert
+        Assert.Contains("agent_id=writer", result);
+        Assert.Contains("conversation_id=123", result);
+        Assert.Contains("page=5", result);
+    }
+
+    /// <summary>
+    /// Verifies that RewriteAgentIdInQueryString works when agent_id is not the first parameter.
+    /// </summary>
+    [Fact]
+    public void RewriteAgentIdInQueryString_AgentIdNotFirst_StillRewrites()
+    {
+        // Arrange
+        var queryString = new QueryString("?page=1&agent_id=editor-agent%2Feditor&limit=10");
+
+        // Act
+        var result = DevUIAggregatorHostedService.RewriteAgentIdInQueryString(queryString, "editor");
+
+        // Assert
+        Assert.Contains("agent_id=editor", result);
+        Assert.DoesNotContain("editor-agent", result);
+    }
+
+    /// <summary>
+    /// Verifies that RewriteAgentIdInQueryString handles special characters in actual agent ID.
+    /// </summary>
+    [Fact]
+    public void RewriteAgentIdInQueryString_SpecialCharsInAgentId_UrlEncodesCorrectly()
+    {
+        // Arrange
+        var queryString = new QueryString("?agent_id=prefix%2Fmy-agent");
+
+        // Act
+        var result = DevUIAggregatorHostedService.RewriteAgentIdInQueryString(queryString, "my-agent");
+
+        // Assert
+        // The result should contain the agent_id with the value properly encoded if needed
+        Assert.Contains("agent_id=my-agent", result);
+    }
+
+    /// <summary>
+    /// Verifies that RewriteAgentIdInQueryString handles an agent_id with no prefix.
+    /// </summary>
+    [Fact]
+    public void RewriteAgentIdInQueryString_NoPrefix_SetsDirectly()
+    {
+        // Arrange
+        var queryString = new QueryString("?agent_id=simple");
+
+        // Act
+        var result = DevUIAggregatorHostedService.RewriteAgentIdInQueryString(queryString, "new-value");
+
+        // Assert
+        Assert.Contains("agent_id=new-value", result);
+        Assert.DoesNotContain("simple", result);
+    }
+
+    /// <summary>
+    /// Verifies that RewriteAgentIdInQueryString adds agent_id even if not originally present.
+    /// </summary>
+    [Fact]
+    public void RewriteAgentIdInQueryString_NoAgentId_AddsAgentId()
+    {
+        // Arrange
+        var queryString = new QueryString("?page=1&limit=10");
+
+        // Act
+        var result = DevUIAggregatorHostedService.RewriteAgentIdInQueryString(queryString, "writer");
+
+        // Assert
+        Assert.Contains("agent_id=writer", result);
+        Assert.Contains("page=1", result);
+        Assert.Contains("limit=10", result);
+    }
+
+    /// <summary>
+    /// Verifies that RewriteAgentIdInQueryString returns proper format starting with ?.
+    /// </summary>
+    [Fact]
+    public void RewriteAgentIdInQueryString_ValidQuery_ReturnsQueryStringFormat()
+    {
+        // Arrange
+        var queryString = new QueryString("?agent_id=test");
+
+        // Act
+        var result = DevUIAggregatorHostedService.RewriteAgentIdInQueryString(queryString, "writer");
+
+        // Assert
+        Assert.StartsWith("?", result);
+    }
+
+    #endregion
+
+    #region Backend Resolution Behavior Tests
+
+    /// <summary>
+    /// Verifies that ResolveBackends returns empty dictionary when no annotations are present.
+    /// These tests verify the expected behavior of the aggregator via the DevUI resource annotations.
+    /// </summary>
+    [Fact]
+    public void DevUIResource_NoAnnotations_ResolveBackendsReturnsEmpty()
+    {
+        // Arrange
+        var builder = DistributedApplication.CreateBuilder();
+        var devui = builder.AddDevUI("devui");
+
+        // Assert - no AgentServiceAnnotation means no backends
+        var annotations = devui.Resource.Annotations
+            .OfType<AgentServiceAnnotation>()
+            .ToList();
+
+        Assert.Empty(annotations);
+    }
+
+    /// <summary>
+    /// Verifies that WithAgentService adds proper annotations for backend resolution.
+    /// </summary>
+    [Fact]
+    public void WithAgentService_AddsAnnotation_ForBackendResolution()
+    {
+        // Arrange
+        var builder = DistributedApplication.CreateBuilder();
+        var devui = builder.AddDevUI("devui");
+        var agentService = CreateMockAgentServiceBuilder(builder, "writer-agent");
+
+        // Act
+        devui.WithAgentService(agentService);
+
+        // Assert
+        var annotation = devui.Resource.Annotations
+            .OfType<AgentServiceAnnotation>()
+            .FirstOrDefault();
+
+        Assert.NotNull(annotation);
+        Assert.Equal("writer-agent", annotation.AgentService.Name);
+    }
+
+    /// <summary>
+    /// Verifies that custom EntityIdPrefix is properly stored in the annotation.
+    /// </summary>
+    [Fact]
+    public void WithAgentService_CustomPrefix_StoresInAnnotation()
+    {
+        // Arrange
+        var builder = DistributedApplication.CreateBuilder();
+        var devui = builder.AddDevUI("devui");
+        var agentService = CreateMockAgentServiceBuilder(builder, "writer-agent");
+
+        // Act
+        devui.WithAgentService(agentService, entityIdPrefix: "custom-writer");
+
+        // Assert
+        var annotation = devui.Resource.Annotations
+            .OfType<AgentServiceAnnotation>()
+            .First();
+
+        Assert.Equal("custom-writer", annotation.EntityIdPrefix);
+    }
+
+    /// <summary>
+    /// Verifies that multiple agent services create multiple annotations for backend resolution.
+    /// </summary>
+    [Fact]
+    public void WithAgentService_MultipleServices_CreatesMultipleAnnotations()
+    {
+        // Arrange
+        var builder = DistributedApplication.CreateBuilder();
+        var devui = builder.AddDevUI("devui");
+        var writerService = CreateMockAgentServiceBuilder(builder, "writer-agent");
+        var editorService = CreateMockAgentServiceBuilder(builder, "editor-agent");
+
+        // Act
+        devui.WithAgentService(writerService);
+        devui.WithAgentService(editorService);
+
+        // Assert
+        var annotations = devui.Resource.Annotations
+            .OfType<AgentServiceAnnotation>()
+            .ToList();
+
+        Assert.Equal(2, annotations.Count);
+        Assert.Contains(annotations, a => a.AgentService.Name == "writer-agent");
+        Assert.Contains(annotations, a => a.AgentService.Name == "editor-agent");
+    }
+
+    #endregion
+
+    #region Entity ID Parsing Tests
+
+    /// <summary>
+    /// Verifies the expected format for prefixed entity IDs in the aggregator.
+    /// </summary>
+    [Theory]
+    [InlineData("writer-agent/writer", "writer-agent", "writer")]
+    [InlineData("editor-agent/editor", "editor-agent", "editor")]
+    [InlineData("custom/my-agent", "custom", "my-agent")]
+    [InlineData("prefix/sub/path", "prefix", "sub/path")]
+    public void PrefixedEntityId_Format_ExtractsCorrectly(string prefixedId, string expectedPrefix, string expectedRest)
+    {
+        // This test documents the expected format for prefixed entity IDs
+        // The aggregator uses "prefix/entityId" format where:
+        // - prefix is typically the resource name or custom prefix
+        // - entityId is the original entity identifier from the backend
+
+        var slashIndex = prefixedId.IndexOf('/');
+        var prefix = prefixedId[..slashIndex];
+        var rest = prefixedId[(slashIndex + 1)..];
+
+        Assert.Equal(expectedPrefix, prefix);
+        Assert.Equal(expectedRest, rest);
+    }
+
+    #endregion
+
+    #region Helper Methods
+
+    /// <summary>
+    /// Creates a mock agent service builder for testing.
+    /// Uses a minimal resource implementation that satisfies IResourceWithEndpoints.
+    /// </summary>
+    private static IResourceBuilder<IResourceWithEndpoints> CreateMockAgentServiceBuilder(
+        IDistributedApplicationBuilder appBuilder,
+        string name)
+    {
+        // Create a mock resource that implements IResourceWithEndpoints
+        var mockResource = new Moq.Mock<IResourceWithEndpoints>();
+        mockResource.Setup(r => r.Name).Returns(name);
+        mockResource.Setup(r => r.Annotations).Returns(new ResourceAnnotationCollection());
+
+        var mockBuilder = new Moq.Mock<IResourceBuilder<IResourceWithEndpoints>>();
+        mockBuilder.Setup(b => b.Resource).Returns(mockResource.Object);
+        mockBuilder.Setup(b => b.ApplicationBuilder).Returns(appBuilder);
+
+        return mockBuilder.Object;
+    }
+
+    #endregion
+}