test: reproduce #396 (v0.3 status.message missing kind/messageId)

Deserializes the exact payload shape from the issue report: a v0.3
task response whose status.message omits both kind and messageId.
Asserts both fields fall back to sensible defaults instead of failing
deserialization.

Author: chopmob-cloud

tests/A2A.V0_3.UnitTests/GitHubIssues/Issue396.cs

@@ -0,0 +1,47 @@
+using System.Text.Json;
+
+namespace A2A.V0_3.UnitTests.GitHubIssues
+{
+    public sealed class Issue396
+    {
+        [Fact]
+        public void Issue_396_Passes()
+        {
+            var json = """
+            {
+              "jsonrpc": "2.0",
+              "id": "1",
+              "result": {
+                "id": "63b2861e-1234-4a1a-9a3a-000000000001",
+                "contextId": "2c727c41-1234-4a1a-9a3a-000000000002",
+                "kind": "task",
+                "status": {
+                  "state": "completed",
+                  "message": {
+                    "role": "agent",
+                    "parts": [ { "kind": "text", "text": "Skill completed." } ]
+                  },
+                  "timestamp": "2026-05-17T15:59:43.401Z"
+                }
+              }
+            }
+            """;
+
+            var deserializedResponseObj = JsonSerializer.Deserialize<JsonRpcResponse>(json, A2AJsonUtilities.DefaultOptions);
+            Assert.NotNull(deserializedResponseObj);
+
+            var task = deserializedResponseObj.Result.Deserialize<AgentTask>(A2AJsonUtilities.DefaultOptions);
+            Assert.NotNull(task);
+
+            Assert.Equal("63b2861e-1234-4a1a-9a3a-000000000001", task.Id);
+            Assert.NotNull(task.Status.Message);
+
+            // kind and messageId were both omitted from status.message; both fall back to
+            // their defaults instead of failing deserialization.
+            Assert.Equal("message", task.Status.Message!.Kind);
+            Assert.False(string.IsNullOrEmpty(task.Status.Message.MessageId));
+            Assert.Equal(MessageRole.Agent, task.Status.Message.Role);
+            Assert.Single(task.Status.Message.Parts);
+        }
+    }
+}