test(search): the long-line, answers and error-output tests make their folder with createTempDir()

Each made its temporary folder by hand and resolved its real path itself
(macOS's temporary folder is behind a link, and the server works with
real paths). createTempDir() does the same.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

Author: mihailt

test/test-search-answers-unchanged.js

@@ -11,10 +11,10 @@
  */
 import assert from 'assert';
 import fs from 'fs';
-import os from 'os';
 import path from 'path';
 import { connectToServer, readSearchAnswer, closeClient } from './helpers/mcp-client.js';
 import { runIfMain } from './helpers/run-if-main.js';
+import { createTempDir } from './helpers/test-env.js';
 
 const MB = 1024 * 1024;
 const PATTERN = 'needle\\w*';
@@ -171,7 +171,7 @@ async function checkNonUtf8Match(client, dir) {
 }
 
 export default async function runTests() {
-  const dir = fs.realpathSync(fs.mkdtempSync(path.join(os.tmpdir(), 'dc-search-answers-')));
+  const dir = createTempDir('dc-search-answers-');
   fs.writeFileSync(path.join(dir, 'guard.js'), `${LINES.join('\n')}\n`);
 
   const cases = [

test/test-search-error-output.js

@@ -7,18 +7,18 @@
  */
 import assert from 'assert';
 import fs from 'fs';
-import os from 'os';
 import path from 'path';
 import { searchManager } from '../dist/search-manager.js';
 import { configManager } from '../dist/config-manager.js';
 import { handleStartSearch } from '../dist/handlers/search-handlers.js';
 import { runIfMain } from './helpers/run-if-main.js';
+import { createTempDir } from './helpers/test-env.js';
 
 const MAX_KEPT_CHARS = 64 * 1024;
 
 export default async function runTests() {
   const originalConfig = await configManager.getConfig();
-  const dir = fs.realpathSync(fs.mkdtempSync(path.join(os.tmpdir(), 'dc-search-errors-')));
+  const dir = createTempDir('dc-search-errors-');
   fs.writeFileSync(path.join(dir, 'a.txt'), 'text\n');
   await configManager.setValue('allowedDirectories', [dir]);
   let sessionId;

test/test-search-long-lines.js

@@ -15,7 +15,6 @@
 import assert from 'assert';
 import { constants } from 'buffer';
 import fs from 'fs';
-import os from 'os';
 import path from 'path';
 import v8 from 'v8';
 import vm from 'vm';
@@ -25,6 +24,7 @@ import { configManager } from '../dist/config-manager.js';
 import { startSearchAndWait } from './helpers/search.js';
 import { connectToServer, readSearchAnswer, closeClient } from './helpers/mcp-client.js';
 import { runIfMain } from './helpers/run-if-main.js';
+import { createTempDir } from './helpers/test-env.js';
 
 v8.setFlagsFromString('--expose-gc');
 const gc = vm.runInNewContext('gc');
@@ -150,7 +150,7 @@ export default async function runTests() {
   const failures = [];
   try {
     for (const [name, run] of cases) {
-      const dir = fs.realpathSync(fs.mkdtempSync(path.join(os.tmpdir(), 'dc-search-long-lines-')));
+      const dir = createTempDir('dc-search-long-lines-');
       try {
         await configManager.setValue('allowedDirectories', [dir]);
         await run(dir);