test_runner: do not spawn run in child processes

lib/internal/test_runner/runner.js

@@ -69,6 +69,7 @@ const {
   convertStringToRegExp,
   countCompletedTest,
   kDefaultPattern,
+  parseCommandLine,
 } = require('internal/test_runner/utils');
 const { Glob } = require('internal/fs/glob');
 const { once } = require('events');
@@ -470,13 +471,22 @@ function run(options) {
   }
 
   const root = createTestTree({ concurrency, timeout, signal });
+  let postRun = () => root.postRun();
+
+  // don't spawn `run` in child processes to prevent infinite loops
+  const { isChildProcess, isChildProcessV8 } = parseCommandLine()
+  if (isChildProcess || isChildProcessV8) {
+    PromisePrototypeThen(PromisePrototypeThen(PromiseResolve(setup?.(root)), []), postRun);
+
+    return root.reporter;
+  }
+
   let testFiles = files ?? createTestFileList();
 
   if (shard) {
     testFiles = ArrayPrototypeFilter(testFiles, (_, index) => index % shard.total === shard.index - 1);
   }
 
-  let postRun = () => root.postRun();
   let filesWatcher;
   if (watch) {
     filesWatcher = watchFiles(testFiles, root, inspectPort, signal, testNamePatterns);

lib/internal/test_runner/utils.js

@@ -235,6 +235,8 @@ function parseCommandLine() {
     testNamePatterns,
     reporters,
     destinations,
+    isChildProcess,
+    isChildProcessV8,
   };
 
   return globalTestOptions;

test/fixtures/test-runner/run_null_files/a.test.mjs

@@ -0,0 +1,3 @@
+import test from 'node:test';
+
+test('this a should pass');

test/fixtures/test-runner/run_null_files/b.test.mjs

@@ -0,0 +1,3 @@
+import test from 'node:test';
+
+test('this b should pass');

test/fixtures/test-runner/run_null_files/run.mjs

@@ -0,0 +1,16 @@
+import { run } from 'node:test';
+import assert from 'node:assert';
+import { tap } from 'node:test/reporters';
+
+const stream = run({
+  timeout: 1000
+})
+  .compose(tap)
+  .pipe(process.stdout)
+
+stream.on('test:fail', (f) => {
+  assert.ok(false)
+});
+stream.on('test:pass', (p) => {
+  assert.ok(false)
+});

test/fixtures/test-runner/run_self_path.mjs

@@ -0,0 +1,22 @@
+import { run, test } from 'node:test';
+import { fileURLToPath } from 'node:url';
+import assert from 'node:assert';
+import { tap } from 'node:test/reporters';
+
+const stream = run({
+  files: [fileURLToPath(import.meta.url)],
+  timeout: 1000
+})
+  .compose(tap)
+  .pipe(process.stdout)
+
+stream.on('test:fail', (f) => {
+  assert.ok(false)
+});
+stream.on('test:pass', (p) => {
+  assert.ok(false)
+});
+
+test('1 + 1 = 2', async () => {
+  assert.strictEqual(1 + 1, 2, '1 + 1 = 2')
+})

test/parallel/test-runner-run.mjs

@@ -3,6 +3,7 @@ import * as fixtures from '../common/fixtures.mjs';
 import { join } from 'node:path';
 import { describe, it, run } from 'node:test';
 import { dot, spec, tap } from 'node:test/reporters';
+import { execFileSync } from 'child_process';
 import assert from 'node:assert';
 
 const testFixtures = fixtures.path('test-runner');
@@ -17,6 +18,23 @@ describe('require(\'node:test\').run', { concurrency: true }, () => {
     for await (const _ of stream);
   });
 
+  it('should run without infinite loops (self path)', { timeout: 10000 }, async () => {
+    execFileSync(
+      process.execPath,
+      ['--test', join(testFixtures, 'run_self_path.mjs')],
+      { timeout: 10000, cwd: testFixtures }
+    );
+  });
+
+  it('should run without infinite loops (Default: files)', { timeout: 10000 }, async () => {
+    const cwd = join(testFixtures, 'run_null_files')
+    execFileSync(
+      process.execPath,
+      ['--test', join(cwd, 'run.mjs')],
+      { timeout: 10000, cwd }
+    );
+  });
+
   it('should fail with non existing file', async () => {
     const stream = run({ files: ['a-random-file-that-does-not-exist.js'] });
     stream.on('test:fail', common.mustCall(1));