diff --git a/lib/internal/main/test_runner.js b/lib/internal/main/test_runner.js
index 9a87a8eac7d41a..7e6f3079a509a9 100644
--- a/lib/internal/main/test_runner.js
+++ b/lib/internal/main/test_runner.js
@@ -18,6 +18,9 @@ const {
   RegExpPrototypeExec,
   StringPrototypeSplit,
 } = primordials;
+let debug = require('internal/util/debuglog').debuglog('test_runner', (fn) => {
+  debug = fn;
+});
 
 prepareMainThreadExecution(false);
 markBootstrapComplete();
@@ -57,8 +60,15 @@ if (shardOption) {
   };
 }
 
-run({ concurrency, inspectPort, watch: getOptionValue('--watch'), setup: setupTestReporters, shard })
-.on('test:fail', (data) => {
+const options = {
+  concurrency,
+  inspectPort,
+  watch: getOptionValue('--watch'),
+  setup: setupTestReporters,
+  shard,
+};
+debug('test runner configuration:', options);
+run(options).on('test:fail', (data) => {
   if (data.todo === undefined || data.todo === false) {
     process.exitCode = kGenericUserError;
   }
diff --git a/test/parallel/test-runner-cli-concurrency.js b/test/parallel/test-runner-cli-concurrency.js
index 9d8dd4f8ce2f82..fbabaf08e27279 100644
--- a/test/parallel/test-runner-cli-concurrency.js
+++ b/test/parallel/test-runner-cli-concurrency.js
@@ -1,45 +1,26 @@
 'use strict';
-const common = require('../common');
-const tmpdir = require('../common/tmpdir');
-const { deepStrictEqual, strictEqual } = require('node:assert');
+require('../common');
+const fixtures = require('../common/fixtures');
+const assert = require('node:assert');
 const { spawnSync } = require('node:child_process');
-const { readdirSync, writeFileSync } = require('node:fs');
-const { join } = require('node:path');
-const { beforeEach, test } = require('node:test');
+const { test } = require('node:test');
+const cwd = fixtures.path('test-runner', 'default-behavior');
+const env = { ...process.env, 'NODE_DEBUG': 'test_runner' };
 
-function createTestFile(name) {
-  writeFileSync(join(tmpdir.path, name), `
-    const fs = require('node:fs');
-
-    fs.unlinkSync(__filename);
-    setTimeout(() => {}, 1_000_000_000);
-  `);
-}
-
-beforeEach(() => {
-  tmpdir.refresh();
-  createTestFile('test-1.js');
-  createTestFile('test-2.js');
+test('default concurrency', async () => {
+  const args = ['--test'];
+  const cp = spawnSync(process.execPath, args, { cwd, env });
+  assert.match(cp.stderr.toString(), /concurrency: true,/);
 });
 
-test('concurrency of one', () => {
-  const cp = spawnSync(process.execPath, ['--test', '--test-concurrency=1'], {
-    cwd: tmpdir.path,
-    timeout: common.platformTimeout(1000),
-  });
-
-  strictEqual(cp.stderr.toString(), '');
-  strictEqual(cp.error.code, 'ETIMEDOUT');
-  deepStrictEqual(readdirSync(tmpdir.path), ['test-2.js']);
+test('concurrency of one', async () => {
+  const args = ['--test', '--test-concurrency=1'];
+  const cp = spawnSync(process.execPath, args, { cwd, env });
+  assert.match(cp.stderr.toString(), /concurrency: 1,/);
 });
 
-test('concurrency of two', () => {
-  const cp = spawnSync(process.execPath, ['--test', '--test-concurrency=2'], {
-    cwd: tmpdir.path,
-    timeout: common.platformTimeout(1000),
-  });
-
-  strictEqual(cp.stderr.toString(), '');
-  strictEqual(cp.error.code, 'ETIMEDOUT');
-  deepStrictEqual(readdirSync(tmpdir.path), []);
+test('concurrency of two', async () => {
+  const args = ['--test', '--test-concurrency=2'];
+  const cp = spawnSync(process.execPath, args, { cwd, env });
+  assert.match(cp.stderr.toString(), /concurrency: 2,/);
 });