feat: add spawnTest harness global

eslint.config.js

@@ -87,7 +87,7 @@ export default defineConfig([
   },
   {
     files: [
-      'tests/**/*.js',
+      'tests/**/*.{mjs,js}',
     ],
     languageOptions: {
       // Only allow ECMAScript built-ins and CTS harness globals.
@@ -101,6 +101,7 @@ export default defineConfig([
         mustNotCall: 'readonly',
         gc: 'readonly',
         gcUntil: 'readonly',
+        spawnTest: 'readonly',
         experimentalFeatures: 'readonly',
         runtimeFeatures: 'readonly',
         onUncaughtException: 'readonly',

implementors/node/child_process.d.ts

@@ -0,0 +1,15 @@
+export interface SpawnTestOptions {
+  cwd?: string;
+}
+
+export interface SpawnTestResult {
+  status: number | null;
+  aborted: boolean;
+  stdout: string;
+  stderr: string;
+}
+
+export function spawnTest(
+  filePath: string,
+  options?: SpawnTestOptions,
+): SpawnTestResult;

implementors/node/child_process.js

@@ -0,0 +1,61 @@
+import { spawnSync } from 'node:child_process';
+import path from 'node:path';
+import { pathToFileURL } from 'node:url';
+
+const HARNESS_MODULE_PATHS = [
+  'features.js',
+  'assert.js',
+  'load-addon.js',
+  'gc.js',
+  'must-call.js',
+  'skip-test.js',
+  'napi-version.js',
+  'child_process.js',
+].map((file) => path.join(import.meta.dirname, file));
+
+// Exit codes that signify the runtime aborted (rather than exiting cleanly with
+// a non-zero status). On POSIX an abort surfaces as a fatal signal; on Windows
+// as one of a small set of exit codes. Mirrors Node.js's
+// `common.nodeProcessAborted`. The POSIX 128+N codes and the Windows NTSTATUS
+// codes share one list because the ranges don't overlap. Keeping this here, in
+// the Node implementor, lets portable tests ask "did it abort?" via the
+// `aborted` flag without encoding any runtime-specific process semantics.
+const ABORT_EXIT_CODES = [132, 133, 134, 139, 0xc0000409, 0xc000001d];
+
+/**
+ * Runs a test file in a fresh Node.js subprocess with the CTS harness globals
+ * pre-loaded, and returns its exit status, whether it aborted, and output.
+ *
+ * @param {string} filePath - Path to the JS/MJS file to execute. Resolved
+ *   against `options.cwd` if relative.
+ * @param {{ cwd?: string }} [options]
+ *   - `cwd`: working directory for the child; defaults to `process.cwd()`.
+ * @returns {{ status: number | null, aborted: boolean, stdout: string, stderr: string }}
+ */
+export const spawnTest = (filePath, options = {}) => {
+  // --expose-gc is mandatory: gc.js (loaded below) throws at import without it.
+  const args = ['--expose-gc'];
+  for (const modulePath of HARNESS_MODULE_PATHS) {
+    // pathToFileURL handles Windows drive letters and backslashes; a bare
+    // 'file://' + path is malformed there (e.g. file://C:\...).
+    args.push('--import', pathToFileURL(modulePath).href);
+  }
+  args.push(filePath);
+
+  const result = spawnSync(process.execPath, args, {
+    cwd: options.cwd ?? process.cwd(),
+    maxBuffer: 100 * 1024 * 1024,
+  });
+  if (result.error) throw result.error;
+  return {
+    status: result.status,
+    aborted: result.signal !== null || ABORT_EXIT_CODES.includes(result.status),
+    stderr: result.stderr?.toString() ?? '',
+    stdout: result.stdout?.toString() ?? '',
+  };
+};
+
+// This module is loaded in both contexts: imported by the parent test runner
+// (tests.ts) and `--import`ed into every spawned child. The side effect below
+// installs `spawnTest` on the child's globalThis so tests can call it directly.
+Object.assign(globalThis, { spawnTest });

implementors/node/tests.ts

@@ -1,52 +1,16 @@
 import assert from 'node:assert';
-import { spawn } from 'node:child_process';
 import fs from 'node:fs';
 import path from 'node:path';
 
+import { spawnTest } from './child_process.js';
+
 assert(
   typeof import.meta.dirname === 'string',
   'Expecting a recent Node.js runtime API version',
 );
 
 const ROOT_PATH = path.resolve(import.meta.dirname, '..', '..');
 const TESTS_ROOT_PATH = path.join(ROOT_PATH, 'tests');
-const FEATURES_MODULE_PATH = path.join(
-  ROOT_PATH,
-  'implementors',
-  'node',
-  'features.js',
-);
-const ASSERT_MODULE_PATH = path.join(
-  ROOT_PATH,
-  'implementors',
-  'node',
-  'assert.js',
-);
-const LOAD_ADDON_MODULE_PATH = path.join(
-  ROOT_PATH,
-  'implementors',
-  'node',
-  'load-addon.js',
-);
-const GC_MODULE_PATH = path.join(ROOT_PATH, 'implementors', 'node', 'gc.js');
-const MUST_CALL_MODULE_PATH = path.join(
-  ROOT_PATH,
-  'implementors',
-  'node',
-  'must-call.js',
-);
-const SKIP_TEST_MODULE_PATH = path.join(
-  ROOT_PATH,
-  'implementors',
-  'node',
-  'skip-test.js',
-);
-const NAPI_VERSION_MODULE_PATH = path.join(
-  ROOT_PATH,
-  'implementors',
-  'node',
-  'napi-version.js',
-);
 
 export function listDirectoryEntries(dir: string) {
   const entries = fs.readdirSync(dir, { withFileTypes: true });
@@ -67,65 +31,24 @@ export function listDirectoryEntries(dir: string) {
   return { directories, files };
 }
 
-export function runFileInSubprocess(
-  cwd: string,
-  filePath: string,
-): Promise<void> {
-  return new Promise((resolve, reject) => {
-    const child = spawn(
-      process.execPath,
-      [
-        // Using file scheme prefix when to enable imports on Windows
-        '--expose-gc',
-        '--import',
-        'file://' + FEATURES_MODULE_PATH,
-        '--import',
-        'file://' + ASSERT_MODULE_PATH,
-        '--import',
-        'file://' + LOAD_ADDON_MODULE_PATH,
-        '--import',
-        'file://' + GC_MODULE_PATH,
-        '--import',
-        'file://' + MUST_CALL_MODULE_PATH,
-        '--import',
-        'file://' + SKIP_TEST_MODULE_PATH,
-        '--import',
-        'file://' + NAPI_VERSION_MODULE_PATH,
-        filePath,
-      ],
-      { cwd },
-    );
-
-    let stderrOutput = '';
-    child.stderr.setEncoding('utf8');
-    child.stderr.on('data', (chunk) => {
-      stderrOutput += chunk;
-    });
-
-    child.stdout.pipe(process.stdout);
-
-    child.on('error', reject);
-
-    child.on('close', (code, signal) => {
-      if (code === 0) {
-        resolve();
-        return;
-      }
-
-      const reason =
-        code !== null ? `exit code ${code}` : `signal ${signal ?? 'unknown'}`;
-      const trimmedStderr = stderrOutput.trim();
-      const stderrSuffix = trimmedStderr ?
-        `\n--- stderr ---\n${trimmedStderr}\n--- end stderr ---` :
-        '';
-      reject(
-        new Error(
-          `Test file ${path.relative(
-            TESTS_ROOT_PATH,
-            filePath,
-          )} failed (${reason})${stderrSuffix}`,
-        ),
-      );
-    });
-  });
+export function runFileInSubprocess(cwd: string, filePath: string): void {
+  const { status, aborted, stdout, stderr } = spawnTest(filePath, { cwd });
+
+  if (stdout) process.stdout.write(stdout);
+
+  if (status === 0) return;
+
+  const reason = aborted ?
+    'aborted' :
+    status !== null ? `exit code ${status}` : 'unknown';
+  const trimmedStderr = stderr.trim();
+  const stderrSuffix = trimmedStderr ?
+    `\n--- stderr ---\n${trimmedStderr}\n--- end stderr ---` :
+    '';
+  throw new Error(
+    `Test file ${path.relative(
+      TESTS_ROOT_PATH,
+      path.join(cwd, filePath),
+    )} failed (${reason})${stderrSuffix}`,
+  );
 }

tests/harness/spawn-test-fail-child.mjs

@@ -0,0 +1,4 @@
+// Spawned by spawn-test.js. Throws an error with a recognizable marker so the
+// parent can assert that stderr was captured and that the non-zero exit status
+// is surfaced.
+throw new Error('spawn-test-fail-marker');

tests/harness/spawn-test-ok-child.mjs

@@ -0,0 +1,5 @@
+// Spawned by spawn-test.js. Confirms harness globals are injected into the
+// child process by checking `assert` exists, then exits 0.
+if (typeof assert !== 'function') {
+  throw new Error('Expected `assert` to be a CTS harness global inside spawned children');
+}

tests/harness/spawn-test.js

@@ -0,0 +1,48 @@
+// spawnTest is a function
+if (typeof spawnTest !== 'function') {
+  throw new Error('Expected a global spawnTest function');
+}
+
+// Successful child: exits 0, stderr empty, and harness globals are available
+// inside the child (the child checks `typeof assert === 'function'` itself).
+{
+  const result = spawnTest('spawn-test-ok-child.mjs');
+  assert.strictEqual(result.status, 0, `ok child exited with status ${result.status}; stderr:\n${result.stderr}`);
+  assert.strictEqual(result.aborted, false);
+  assert.strictEqual(result.stderr, '');
+}
+
+// Failing child: non-zero status and stderr contains the thrown marker.
+{
+  const result = spawnTest('spawn-test-fail-child.mjs');
+  assert.notStrictEqual(result.status, 0, 'fail child should exit non-zero');
+  // A thrown error is a clean non-zero exit, not an abnormal termination.
+  assert.strictEqual(result.aborted, false);
+  if (!result.stderr.includes('spawn-test-fail-marker')) {
+    throw new Error(`Expected stderr to include the failure marker, got:\n${result.stderr}`);
+  }
+}
+
+// Result shape: all four fields are present.
+{
+  const result = spawnTest('spawn-test-ok-child.mjs');
+  for (const key of ['status', 'aborted', 'stdout', 'stderr']) {
+    if (!(key in result)) {
+      throw new Error(`Expected spawnTest result to have "${key}" field`);
+    }
+  }
+  assert.strictEqual(typeof result.aborted, 'boolean');
+  assert.strictEqual(typeof result.stdout, 'string');
+  assert.strictEqual(typeof result.stderr, 'string');
+}
+
+// cwd is forwarded to the child: running from the parent of tests/harness
+// makes the bare child filename unresolvable. The child's stderr must name
+// the specific file Node tried to load, proving cwd actually shifted.
+{
+  const result = spawnTest('spawn-test-ok-child.mjs', { cwd: '..' });
+  assert.notStrictEqual(result.status, 0, 'expected cwd ".." to make the child filename unresolvable');
+  if (!result.stderr.includes('spawn-test-ok-child.mjs')) {
+    throw new Error(`Expected stderr to reference the unresolved child filename, got:\n${result.stderr}`);
+  }
+}