fix json renderer test isolation

Author: Telli

src/SharpClaw.Code.Cli/Rendering/JsonOutputRenderer.cs

@@ -12,9 +12,13 @@ namespace SharpClaw.Code.Cli.Rendering;
 /// <summary>
 /// Renders command and prompt results as JSON.
 /// </summary>
-public sealed class JsonOutputRenderer(ILogger<JsonOutputRenderer>? logger = null) : IOutputRenderer
+public sealed class JsonOutputRenderer(
+    ILogger<JsonOutputRenderer>? logger = null,
+    TextWriter? outputWriter = null) : IOutputRenderer
 {
     private readonly ILogger<JsonOutputRenderer> _logger = logger ?? NullLogger<JsonOutputRenderer>.Instance;
+    private readonly TextWriter? _outputWriter = outputWriter;
+
     /// <inheritdoc />
     public OutputFormat Format => OutputFormat.Json;
 
@@ -47,15 +51,18 @@ public Task RenderCommandResultAsync(CommandResult result, CancellationToken can
                 dataRaw),
             JsonOutputJsonContext.Default.JsonCommandEnvelope);
 
-        return Console.Out.WriteLineAsync(json.AsMemory(), cancellationToken);
+        return WriteLineAsync(json, cancellationToken);
     }
 
     /// <inheritdoc />
     public Task RenderTurnExecutionResultAsync(TurnExecutionResult result, CancellationToken cancellationToken)
     {
         var json = JsonSerializer.Serialize(result, ProtocolJsonContext.Default.TurnExecutionResult);
-        return Console.Out.WriteLineAsync(json.AsMemory(), cancellationToken);
+        return WriteLineAsync(json, cancellationToken);
     }
+
+    private Task WriteLineAsync(string json, CancellationToken cancellationToken)
+        => (_outputWriter ?? Console.Out).WriteLineAsync(json.AsMemory(), cancellationToken);
 }
 
 internal sealed record JsonCommandEnvelope(

tests/SharpClaw.Code.IntegrationTests/Smoke/JsonOutputRendererTests.cs

@@ -17,26 +17,17 @@ public sealed class JsonOutputRendererTests
     [Fact]
     public async Task RenderCommandResultAsync_should_wrap_data_payload_in_stable_envelope()
     {
-        var renderer = new JsonOutputRenderer();
         using var writer = new StringWriter();
-        var originalOut = Console.Out;
-        Console.SetOut(writer);
+        var renderer = new JsonOutputRenderer(outputWriter: writer);
 
-        try
-        {
-            await renderer.RenderCommandResultAsync(
-                new CommandResult(
-                    Succeeded: true,
-                    ExitCode: 0,
-                    OutputFormat: OutputFormat.Text,
-                    Message: "ok",
-                    DataJson: """{"version":"1.2.3"}"""),
-                CancellationToken.None);
-        }
-        finally
-        {
-            Console.SetOut(originalOut);
-        }
+        await renderer.RenderCommandResultAsync(
+            new CommandResult(
+                Succeeded: true,
+                ExitCode: 0,
+                OutputFormat: OutputFormat.Text,
+                Message: "ok",
+                DataJson: """{"version":"1.2.3"}"""),
+            CancellationToken.None);
 
         using var document = JsonDocument.Parse(writer.ToString());
         var root = document.RootElement;
@@ -54,26 +45,17 @@ await renderer.RenderCommandResultAsync(
     [Fact]
     public async Task RenderCommandResultAsync_should_fall_back_to_data_raw_for_invalid_payloads()
     {
-        var renderer = new JsonOutputRenderer();
         using var writer = new StringWriter();
-        var originalOut = Console.Out;
-        Console.SetOut(writer);
+        var renderer = new JsonOutputRenderer(outputWriter: writer);
 
-        try
-        {
-            await renderer.RenderCommandResultAsync(
-                new CommandResult(
-                    Succeeded: false,
-                    ExitCode: 1,
-                    OutputFormat: OutputFormat.Text,
-                    Message: "bad",
-                    DataJson: "{not-json"),
-                CancellationToken.None);
-        }
-        finally
-        {
-            Console.SetOut(originalOut);
-        }
+        await renderer.RenderCommandResultAsync(
+            new CommandResult(
+                Succeeded: false,
+                ExitCode: 1,
+                OutputFormat: OutputFormat.Text,
+                Message: "bad",
+                DataJson: "{not-json"),
+            CancellationToken.None);
 
         using var document = JsonDocument.Parse(writer.ToString());
         var root = document.RootElement;