From 201a3865d09f99ee019dc3bed8c8623c0613c82d Mon Sep 17 00:00:00 2001
From: DominikKaloc <dominik.kaloc@lego.com>
Date: Tue, 9 Sep 2025 13:21:44 +0200
Subject: [PATCH] chore: empty channels allowed

---
 src/LEGO.AsyncAPI/Models/AsyncApiDocument.cs              | 2 +-
 .../Validation/Rules/AsyncApiDocumentRules.cs             | 3 +--
 test/LEGO.AsyncAPI.Tests/AsyncApiDocumentBuilder.cs       | 6 ++++++
 test/LEGO.AsyncAPI.Tests/AsyncApiDocumentV2Tests.cs       | 8 ++++++++
 4 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/src/LEGO.AsyncAPI/Models/AsyncApiDocument.cs b/src/LEGO.AsyncAPI/Models/AsyncApiDocument.cs
index 5d90e7a8..0359d083 100644
--- a/src/LEGO.AsyncAPI/Models/AsyncApiDocument.cs
+++ b/src/LEGO.AsyncAPI/Models/AsyncApiDocument.cs
@@ -44,7 +44,7 @@ public class AsyncApiDocument : IAsyncApiExtensible, IAsyncApiSerializable
         /// <summary>
         /// REQUIRED. The available channels and messages for the API.
         /// </summary>
-        public IDictionary<string, AsyncApiChannel> Channels { get; set; } = new Dictionary<string, AsyncApiChannel>();
+        public IDictionary<string, AsyncApiChannel> Channels { get; set; }
 
         /// <summary>
         /// an element to hold various schemas for the specification.
diff --git a/src/LEGO.AsyncAPI/Validation/Rules/AsyncApiDocumentRules.cs b/src/LEGO.AsyncAPI/Validation/Rules/AsyncApiDocumentRules.cs
index e82f3c7c..2f759905 100644
--- a/src/LEGO.AsyncAPI/Validation/Rules/AsyncApiDocumentRules.cs
+++ b/src/LEGO.AsyncAPI/Validation/Rules/AsyncApiDocumentRules.cs
@@ -37,8 +37,7 @@ public static class AsyncApiDocumentRules
                     context.Enter("channels");
                     try
                     {
-                        // MUST have at least 1 channel
-                        if (document.Channels == null || !document.Channels.Keys.Any())
+                        if (document.Channels == null)
                         {
                             context.CreateError(
                                 nameof(DocumentRequiredFields),
diff --git a/test/LEGO.AsyncAPI.Tests/AsyncApiDocumentBuilder.cs b/test/LEGO.AsyncAPI.Tests/AsyncApiDocumentBuilder.cs
index 2967fd8c..3a5ad497 100644
--- a/test/LEGO.AsyncAPI.Tests/AsyncApiDocumentBuilder.cs
+++ b/test/LEGO.AsyncAPI.Tests/AsyncApiDocumentBuilder.cs
@@ -3,6 +3,7 @@
 namespace LEGO.AsyncAPI.Tests
 {
     using System;
+    using System.Collections.Generic;
     using LEGO.AsyncAPI.Models;
     using LEGO.AsyncAPI.Models.Interfaces;
 
@@ -42,6 +43,11 @@ public AsyncApiDocumentBuilder WithDefaultContentType(string contentType = "appl
 
         public AsyncApiDocumentBuilder WithChannel(string key, AsyncApiChannel channel)
         {
+            if (this.document.Channels == null)
+            {
+                this.document.Channels = new Dictionary<string, AsyncApiChannel>();
+            }
+
             this.document.Channels.Add(key, channel);
             return this;
         }
diff --git a/test/LEGO.AsyncAPI.Tests/AsyncApiDocumentV2Tests.cs b/test/LEGO.AsyncAPI.Tests/AsyncApiDocumentV2Tests.cs
index 9b863969..94c09dbe 100644
--- a/test/LEGO.AsyncAPI.Tests/AsyncApiDocumentV2Tests.cs
+++ b/test/LEGO.AsyncAPI.Tests/AsyncApiDocumentV2Tests.cs
@@ -1154,6 +1154,10 @@ public void Serialize_WithBindingReferences_SerializesDeserializes()
                     },
                 },
             };
+            if (doc.Channels == null)
+            {
+                doc.Channels = new Dictionary<string, AsyncApiChannel>();
+            }
             doc.Channels.Add(
                 "testChannel",
                 new AsyncApiChannelReference("#/components/channels/otherchannel"));
@@ -1212,6 +1216,10 @@ public void Serializev2_WithBindings_Serializes()
                 Protocol = "pulsar+ssl",
                 Url = "example.com",
             });
+            if (doc.Channels == null)
+            {
+                doc.Channels = new Dictionary<string, AsyncApiChannel>();
+            }
             doc.Channels.Add(
                 "testChannel",
                 new AsyncApiChannel