.NET: Expand Workflow Unit Test Coverage (#5390)

* refactor: remove dead code

* refactor: remove ignore YieldsMessageAttribute

- the correct one to use is YieldsOutputAttribute
- fixes a comment that mistakenly refers to `.YieldsMessage()` which does not exist.

* fix: ChatForwardingExecutor does not use correct role for string messages

- make ChatForwardingExecutor use its configured role for string messages rather than always use ChatRole.User
- add ChatForwardingExecutor tests

* fixup: remove unused attribute

* test: Add tests for failure when .AsAgent used on a non-ChatProtocol workflow

* test: Add FunctionExecutor tests

- also fixes Send and YieldOutput type registration for synchronous output-returning delegates

* test: Suppress CodeCoverage for obsolete names

* fix: Re-add Obsolete attributes

- avoid hard-breaking change
- properly notify users that these attributes get ignored

dotnet/src/Microsoft.Agents.AI.Workflows.Generators/Analysis/SemanticAnalyzer.cs

@@ -254,7 +254,7 @@ internal static class SemanticAnalyzer
 
     /// <summary>
     /// Combines ClassProtocolInfo results into an AnalysisResult for classes that only have IO attributes
-    /// (no [MessageHandler] methods). This generates only .SendsMessage/.YieldsMessage calls in the protocol
+    /// (no [MessageHandler] methods). This generates only .SendsMessage/.YieldsOutput calls in the protocol
     /// configuration.
     /// </summary>
     /// <remarks>

dotnet/src/Microsoft.Agents.AI.Workflows/AIAgentsAbstractionsExtensions.cs

@@ -9,17 +9,6 @@ namespace Microsoft.Agents.AI.Workflows;
 
 internal static class AIAgentsAbstractionsExtensions
 {
-    public static ChatMessage ToChatMessage(this AgentResponseUpdate update) =>
-        new()
-        {
-            AuthorName = update.AuthorName,
-            Contents = update.Contents,
-            Role = update.Role ?? ChatRole.User,
-            CreatedAt = update.CreatedAt,
-            MessageId = update.MessageId,
-            RawRepresentation = update.RawRepresentation ?? update,
-        };
-
     public static ChatMessage ChatAssistantToUserIfNotFromNamed(this ChatMessage message, string agentName)
         => message.ChatAssistantToUserIfNotFromNamed(agentName, out _, false);
 

dotnet/src/Microsoft.Agents.AI.Workflows/ChatForwardingExecutor.cs

@@ -47,7 +47,7 @@ public sealed class ChatForwardingExecutor(string id, ChatForwardingExecutorOpti
             if (this._stringMessageChatRole.HasValue)
             {
                 routeBuilder = routeBuilder.AddHandler<string>(
-                    (message, context) => context.SendMessageAsync(new ChatMessage(ChatRole.User, message)));
+                    (message, context) => context.SendMessageAsync(new ChatMessage(this._stringMessageChatRole.Value, message)));
             }
 
             routeBuilder.AddHandler<ChatMessage>(ForwardMessageAsync)

dotnet/src/Microsoft.Agents.AI.Workflows/FunctionExecutor.cs

@@ -73,7 +73,14 @@ public class FunctionExecutor<TInput>(string id,
         ExecutorOptions? options = null,
         IEnumerable<Type>? sentMessageTypes = null,
         IEnumerable<Type>? outputTypes = null,
-        bool declareCrossRunShareable = false) : this(id, WrapAction(handlerSync, out var attributeSentTypes, out var attributeYieldTypes), options, attributeSentTypes.Concat(sentMessageTypes ?? []), attributeYieldTypes.Concat(outputTypes ?? []), declareCrossRunShareable)
+        bool declareCrossRunShareable = false) : this(id,
+                                                      WrapAction(handlerSync,
+                                                                 out var attributeSentTypes,
+                                                                 out var attributeYieldTypes),
+                                                      options,
+                                                      attributeSentTypes.Concat(sentMessageTypes ?? []),
+                                                      attributeYieldTypes.Concat(outputTypes ?? []),
+                                                      declareCrossRunShareable)
     {
     }
 }
@@ -96,8 +103,18 @@ public class FunctionExecutor<TInput, TOutput>(string id,
         IEnumerable<Type>? outputTypes = null,
         bool declareCrossRunShareable = false) : Executor<TInput, TOutput>(id, options, declareCrossRunShareable)
 {
-    internal static Func<TInput, IWorkflowContext, CancellationToken, ValueTask<TOutput>> WrapFunc(Func<TInput, IWorkflowContext, CancellationToken, TOutput> handlerSync)
+    internal static Func<TInput, IWorkflowContext, CancellationToken, ValueTask<TOutput>> WrapFunc(Func<TInput, IWorkflowContext, CancellationToken, TOutput> handlerSync, out IEnumerable<Type> sentTypes, out IEnumerable<Type> yieldedTypes)
     {
+        if (handlerSync.Method != null)
+        {
+            MethodInfo method = handlerSync.Method;
+            (sentTypes, yieldedTypes) = method.GetAttributeTypes();
+        }
+        else
+        {
+            sentTypes = yieldedTypes = [];
+        }
+
         return RunFuncAsync;
 
         ValueTask<TOutput> RunFuncAsync(TInput input, IWorkflowContext workflowContext, CancellationToken cancellationToken)
@@ -133,7 +150,14 @@ public class FunctionExecutor<TInput, TOutput>(string id,
         ExecutorOptions? options = null,
         IEnumerable<Type>? sentMessageTypes = null,
         IEnumerable<Type>? outputTypes = null,
-        bool declareCrossRunShareable = false) : this(id, WrapFunc(handlerSync), options, sentMessageTypes, outputTypes, declareCrossRunShareable)
+        bool declareCrossRunShareable = false) : this(id,
+                                                      WrapFunc(handlerSync,
+                                                               out var attributeSentTypes,
+                                                               out var attributeYieldTypes),
+                                                      options,
+                                                      attributeSentTypes.Concat(sentMessageTypes ?? []),
+                                                      attributeYieldTypes.Concat(outputTypes ?? []),
+                                                      declareCrossRunShareable)
     {
     }
 }

dotnet/src/Microsoft.Agents.AI.Workflows/HandoffWorkflowBuilder.cs

@@ -20,6 +20,7 @@ internal static class DiagnosticConstants
 }
 
 /// <inheritdoc/>
+[ExcludeFromCodeCoverage] // This is obsolete, and 1:1 equivalent to HandoffWorkflowBuilder (no "s")
 [Obsolete("Prefer HandoffWorkflowBuilder (no 's') instead, which has the same API but the preferred name. This will be removed in a future release before GA.")]
 #pragma warning disable MAAIW001 // Type is for evaluation purposes only and is subject to change or removal in future updates. Suppress this diagnostic to proceed.
 public sealed class HandoffsWorkflowBuilder(AIAgent initialAgent) : HandoffWorkflowBuilderCore<HandoffsWorkflowBuilder>(initialAgent)

dotnet/src/Microsoft.Agents.AI.Workflows/ObsoleteAttributes.cs

@@ -29,6 +29,7 @@ namespace Microsoft.Agents.AI.Workflows;
 /// }
 /// </code>
 /// </example>
+[Obsolete("Use YieldsOutput instead. The Code Generator and the runtime attribute-based type mapping ignore this attribute.")]
 [AttributeUsage(AttributeTargets.Class, AllowMultiple = true, Inherited = true)]
 public sealed class YieldsMessageAttribute : Attribute
 {
@@ -47,3 +48,25 @@ public sealed class YieldsMessageAttribute : Attribute
         this.Type = Throw.IfNull(type);
     }
 }
+
+/// <summary>
+/// This attribute indicates that a message handler streams messages during its execution.
+/// </summary>
+[Obsolete("This attribute does not do anything. The Code Generator and the runtime attribute-based type mapping ignore this attribute.")]
+[AttributeUsage(AttributeTargets.Class | AttributeTargets.Method, AllowMultiple = true)]
+public sealed class StreamsMessageAttribute : Attribute
+{
+    /// <summary>
+    /// The type of the message that the handler yields.
+    /// </summary>
+    public Type Type { get; }
+
+    /// <summary>
+    /// Indicates that the message handler yields streaming messages during the course of execution.
+    /// </summary>
+    public StreamsMessageAttribute(Type type)
+    {
+        // This attribute is used to mark executors that yield messages.
+        this.Type = Throw.IfNull(type);
+    }
+}

dotnet/src/Microsoft.Agents.AI.Workflows/StreamsMessageAttribute.cs

@@ -1,27 +0,0 @@
-// Copyright (c) Microsoft. All rights reserved.
-
-using System;
-using Microsoft.Shared.Diagnostics;
-
-namespace Microsoft.Agents.AI.Workflows;
-
-/// <summary>
-/// This attribute indicates that a message handler streams messages during its execution.
-/// </summary>
-[AttributeUsage(AttributeTargets.Class | AttributeTargets.Method, AllowMultiple = true)]
-public sealed class StreamsMessageAttribute : Attribute
-{
-    /// <summary>
-    /// The type of the message that the handler yields.
-    /// </summary>
-    public Type Type { get; }
-
-    /// <summary>
-    /// Indicates that the message handler yields streaming messages during the course of execution.
-    /// </summary>
-    public StreamsMessageAttribute(Type type)
-    {
-        // This attribute is used to mark executors that yield messages.
-        this.Type = Throw.IfNull(type);
-    }
-}