Stabilize UTF-8 symbol worker test startup (#4937)

TESTING_GUIDE.md

@@ -390,7 +390,7 @@ Use `docs/test-doc-maintenance-plan.md` before moving oversized suites or adding
 - `IndexCommandRunnerTests.SymbolExtractionWorker_LegacyEnvironmentHooksAreIgnored_Issue3398`
   launches the isolated symbol worker to prove legacy worker environment variables are ignored. Its callback budget includes process startup and is intentionally wider than ordinary in-process checks so local process load does not turn the legacy-env regression check into a timeout flake (#3863).
 - `IndexCommandRunnerTests.SymbolExtractionWorker_Utf8RequestsPreserveUnicodeAcrossLanguages`
-  reuses one isolated worker for C#, Java, TypeScript, Python, Go, and Rust requests whose content and paths contain Japanese text. It keeps direct UTF-8 request framing language-neutral and protects Unicode fidelity without creating a large fixture.
+  reuses one isolated worker for C#, Java, TypeScript, Python, Go, and Rust requests whose content and paths contain Japanese text. It first sends an ASCII warm-up with the wider test-only startup budget so parallel net8.0/net9.0 process-startup contention is separated from callback timing, then keeps every Unicode request on the ordinary five-second callback budget. This preserves language-neutral direct UTF-8 request framing and Unicode fidelity without weakening the production worker timeout contract or creating a large fixture (#4937).
 - `IndexCommandRunnerTests.SymbolExtractionWorker_StreamResponseWritesBomlessUtf8Frame`
   exercises the production stream-response overload with a Japanese C# symbol and verifies one BOM-less, newline-terminated UTF-8 JSON frame. Keep the `StringWriter` protocol tests as the in-process diagnostic path while this test protects process stdout framing.
 - `BoundedLineReaderTests.ReadUtf8LineAsync_BuffersFramesWithoutDecoding`, `ReadUtf8LineAsync_EnforcesByteLimitBeforeGrowth`, and `ReadUtf8LineAsync_HandlesCrLfAcrossBufferBoundary`
@@ -1347,7 +1347,7 @@ dotnet test --filter "FullyQualifiedName~GitHelperTests"
 - `IndexCommandRunnerTests.SymbolExtractionWorker_LegacyEnvironmentHooksAreIgnored_Issue3398`
   isolated symbol worker を起動し、legacy worker 環境変数が無視されることを検証します。この callback budget はプロセス起動時間も含むため、通常の in-process チェックより意図的に広く取り、ローカル負荷で legacy-env 回帰テストが timeout flake にならないようにします（#3863）。
 - `IndexCommandRunnerTests.SymbolExtractionWorker_Utf8RequestsPreserveUnicodeAcrossLanguages`
-  1つの isolated worker を再利用し、日本語の content と path を含む C#、Java、TypeScript、Python、Go、Rust の request を順に送ります。大規模 fixture を作らず、direct UTF-8 request framing の言語非依存性と Unicode fidelity を固定します。
+  1つの isolated worker を再利用し、日本語の content と path を含む C#、Java、TypeScript、Python、Go、Rust の request を順に送ります。最初に test 専用の広い startup budget で ASCII warm-up を行い、net8.0/net9.0 の並列 process 起動競合と callback の計測を分離したうえで、すべての Unicode request を通常の5秒 callback budget で検証します。production worker の timeout 契約を緩めず、大規模 fixture を作ることなく direct UTF-8 request framing の言語非依存性と Unicode fidelity を固定します（#4937）。
 - `IndexCommandRunnerTests.SymbolExtractionWorker_StreamResponseWritesBomlessUtf8Frame`
   日本語の C# symbol で本番用 stream-response overload を実行し、BOM なし・改行終端の UTF-8 JSON frame が1件出ることを検証します。`StringWriter` の protocol tests は in-process diagnostic 経路として維持し、このテストで process stdout framing を固定します。
 - `BoundedLineReaderTests.ReadUtf8LineAsync_BuffersFramesWithoutDecoding`、`ReadUtf8LineAsync_EnforcesByteLimitBeforeGrowth`、`ReadUtf8LineAsync_HandlesCrLfAcrossBufferBoundary`

changelog.d/unreleased/4937.internal.md

@@ -0,0 +1,16 @@
+---
+category: internal
+issues:
+  - 4937
+affected:
+  - tests/CodeIndex.Tests/IndexCommandRunnerTests.cs
+  - TESTING_GUIDE.md
+---
+
+## English
+
+- **The cross-language UTF-8 symbol-worker regression test now separates process startup from callback timing (#4937)** — the test warms its reusable isolated worker with a dedicated 30-second test-only startup budget, then verifies every Unicode request under the existing five-second callback budget so parallel net8.0/net9.0 startup contention no longer causes a false timeout without changing the production contract.
+
+## 日本語
+
+- **言語横断 UTF-8 symbol-worker 回帰テストで process 起動と callback 計測を分離しました (#4937)** — 再利用する isolated worker を test 専用の30秒 startup budget で warm-up してから、すべての Unicode request を既存の5秒 callback budget で検証するため、production 契約を変更せずに net8.0/net9.0 の並列起動競合による誤 timeout を防ぎます。

tests/CodeIndex.Tests/IndexCommandRunnerTests.cs

@@ -23,7 +23,8 @@ namespace CodeIndex.Tests;
 [Collection("SQLite pool sensitive")]
 public partial class IndexCommandRunnerTests
 {
-    private static readonly TimeSpan LegacyEnvironmentHookWorkerBudget = TimeSpan.FromSeconds(30);
+    private static readonly TimeSpan SymbolWorkerStartupBudget = TimeSpan.FromSeconds(30);
+    private static readonly TimeSpan SymbolWorkerRequestBudget = TimeSpan.FromSeconds(5);
     private static readonly object FullScanContentLoadHookGate = new();
 
     private readonly JsonSerializerOptions _jsonOptions = new()
@@ -476,7 +477,7 @@ public void SymbolExtractionWorker_LegacyEnvironmentHooksAreIgnored_Issue3398()
                     "public class App { }\n",
                     Path.Combine(projectRoot, "App.cs"),
                     projectRoot,
-                    LegacyEnvironmentHookWorkerBudget);
+                    SymbolWorkerStartupBudget);
 
                 Assert.True(result.Success, result.WorkerError);
                 Assert.False(result.TimedOut);
@@ -507,6 +508,16 @@ public void SymbolExtractionWorker_Utf8RequestsPreserveUnicodeAcrossLanguages()
                 (Lang: "rust", Extension: ".rs", Content: "// 顧客\npub struct Customer {}\n"),
             };
             using var worker = new SymbolExtractionWorkerClient();
+            var warmup = worker.Invoke(
+                0,
+                "csharp",
+                "public class StartupProbe { }\n",
+                Path.Combine(projectRoot, "StartupProbe.cs"),
+                projectRoot,
+                SymbolWorkerStartupBudget);
+
+            Assert.False(warmup.TimedOut, "symbol worker startup exceeded the test-only startup budget");
+            Assert.True(warmup.Success, $"symbol worker startup: {warmup.WorkerError}");
 
             foreach (var testCase in cases)
             {
@@ -516,8 +527,11 @@ public void SymbolExtractionWorker_Utf8RequestsPreserveUnicodeAcrossLanguages()
                     testCase.Content,
                     Path.Combine(sourceDirectory, "顧客" + testCase.Extension),
                     projectRoot,
-                    TimeSpan.FromSeconds(5));
+                    SymbolWorkerRequestBudget);
 
+                Assert.False(
+                    result.TimedOut,
+                    $"{testCase.Lang}: symbol worker callback exceeded the request budget after startup warm-up");
                 Assert.True(result.Success, $"{testCase.Lang}: {result.WorkerError}");
                 Assert.Contains(result.Symbols!, symbol => symbol.Name == "Customer");
             }