test: deflake inspector setup and runner timeouts

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

@@ -0,0 +1,11 @@
+import test, { after } from 'node:test';
+
+// Keep the event loop alive until both tests time out.
+const interval = setInterval(() => {}, 1000);
+after(() => clearInterval(interval));
+
+test('pending promise', () => new Promise(() => {}));
+
+test('pending assertion plan', (t) => {
+  t.plan(1, { wait: true });
+});

test/parallel/test-inspector-async-hook-setup-at-signal.js

@@ -33,7 +33,6 @@ function waitUntilDebugged() {
 
 // This function is called by the inspector client (session)
 function setupTimeoutWithBreak() {
-  clearInterval(waiting);
   process._rawDebug('Debugger ready, setting up timeout with a break');
   setTimeout(() => { debugger; }, 50);
 }
@@ -46,16 +45,20 @@ async function waitForInitialSetup(session) {
 
 async function setupTimeoutForStackTrace(session) {
   console.error('[test]', 'Setting up timeout for async stack trace');
+  // Async hook setup is deferred when requested from a V8 interrupt. Let the
+  // event loop finish that setup before creating the timeout whose stack we test.
   await session.send([
     { 'method': 'Runtime.evaluate',
-      'params': { expression: 'setupTimeoutWithBreak()' } },
+      'params': {
+        expression: 'clearInterval(waiting); setImmediate(setupTimeoutWithBreak)',
+      } },
     { 'method': 'Debugger.resume' },
   ]);
 }
 
 async function checkAsyncStackTrace(session) {
   console.error('[test]', 'Verify basic properties of asyncStackTrace');
-  const paused = await session.waitForBreakOnLine(23, '[eval]');
+  const paused = await session.waitForBreakOnLine(22, '[eval]');
   assert(paused.params.asyncStackTrace,
          `${Object.keys(paused.params)} contains "asyncStackTrace" property`);
   assert(paused.params.asyncStackTrace.description, 'Timeout');

test/parallel/test-runner-run.mjs

@@ -90,7 +90,7 @@ describe('require(\'node:test\').run', { concurrency: true }, () => {
 
   it('should support timeout', async () => {
     const stream = run({ timeout: 50, files: [
-      fixtures.path('test-runner', 'plan', 'timeout-basic.mjs'),
+      fixtures.path('test-runner', 'run-timeout.mjs'),
     ] });
     stream.on('test:fail', common.mustCall((data) => {
       assert.strictEqual(data.details.error.failureType, 'testTimeoutFailure');