test: fix flaky test-runner-cli-concurrency.js

This test was flaky on Windows when trying to clean up the
tmp directory between tests. This commit updates the test to
not delete anything between tests.

Fixes: nodejs#50101

test/parallel/test-runner-cli-concurrency.js

@@ -1,45 +1,57 @@
 'use strict';
 const common = require('../common');
 const tmpdir = require('../common/tmpdir');
-const { deepStrictEqual, strictEqual } = require('node:assert');
-const { spawnSync } = require('node:child_process');
-const { readdirSync, writeFileSync } = require('node:fs');
+const { spawn } = require('node:child_process');
+const { mkdirSync, readdirSync, writeFileSync } = require('node:fs');
 const { join } = require('node:path');
-const { beforeEach, test } = require('node:test');
+const { test } = require('node:test');
+const { setTimeout: sleep } = require('node:timers/promises');
+const { isDeepStrictEqual } = require('node:util');
 
 function createTestFile(name) {
-  writeFileSync(join(tmpdir.path, name), `
+  const path = join(tmpdir.path, name);
+  writeFileSync(path, `
     const fs = require('node:fs');
+    const { join } = require('node:path');
 
-    fs.unlinkSync(__filename);
+    fs.writeFileSync(join(process.cwd(), '${name}.out'), 'x');
     setTimeout(() => {}, 1_000_000_000);
   `);
+  return path;
 }
 
-beforeEach(() => {
-  tmpdir.refresh();
-  createTestFile('test-1.js');
-  createTestFile('test-2.js');
-});
+let cnt = 0;
+function nextDir() {
+  const path = join(tmpdir.path, String(cnt));
+  cnt++;
+  mkdirSync(path);
+  return path;
+}
+
+async function waitForFiles(dir, files) {
+  while (!isDeepStrictEqual(readdirSync(dir), files)) {
+    await sleep(common.platformTimeout(1000));
+  }
+}
+
+tmpdir.refresh();
+const test1 = createTestFile('test-1.js');
+const test2 = createTestFile('test-2.js');
 
-test('concurrency of one', () => {
-  const cp = spawnSync(process.execPath, ['--test', '--test-concurrency=1'], {
-    cwd: tmpdir.path,
-    timeout: common.platformTimeout(1000),
-  });
+test('concurrency of one', async () => {
+  const cwd = nextDir();
+  const args = ['--test', '--test-concurrency=1', test1, test2];
+  const cp = spawn(process.execPath, args, { cwd });
 
-  strictEqual(cp.stderr.toString(), '');
-  strictEqual(cp.error.code, 'ETIMEDOUT');
-  deepStrictEqual(readdirSync(tmpdir.path), ['test-2.js']);
+  await waitForFiles(cwd, ['test-1.js.out']);
+  cp.kill();
 });
 
-test('concurrency of two', () => {
-  const cp = spawnSync(process.execPath, ['--test', '--test-concurrency=2'], {
-    cwd: tmpdir.path,
-    timeout: common.platformTimeout(1000),
-  });
+test('concurrency of two', async () => {
+  const cwd = nextDir();
+  const args = ['--test', '--test-concurrency=2', test1, test2];
+  const cp = spawn(process.execPath, args, { cwd });
 
-  strictEqual(cp.stderr.toString(), '');
-  strictEqual(cp.error.code, 'ETIMEDOUT');
-  deepStrictEqual(readdirSync(tmpdir.path), []);
+  await waitForFiles(cwd, ['test-1.js.out', 'test-2.js.out']);
+  cp.kill();
 });