test_runner: reset count on watch mode

lib/internal/test_runner/runner.js

@@ -4,10 +4,12 @@ const {
   ArrayPrototypeFilter,
   ArrayPrototypeForEach,
   ArrayPrototypeIncludes,
+  ArrayPrototypeIndexOf,
   ArrayPrototypePush,
   ArrayPrototypeSlice,
   ArrayPrototypeSome,
   ArrayPrototypeSort,
+  ArrayPrototypeSplice,
   FunctionPrototypeCall,
   Number,
   ObjectAssign,
@@ -325,7 +327,17 @@ function runTestFile(path, root, inspectPort, filesWatcher) {
       throw err;
     }
   });
-  return subtest.start();
+  const promise = subtest.start();
+  if (filesWatcher) {
+    return PromisePrototypeThen(promise, () => {
+      const index = ArrayPrototypeIndexOf(root.subtests, subtest);
+      if (index !== -1) {
+        ArrayPrototypeSplice(root.subtests, index, 1);
+        root.waitingOn--;
+      }
+    });
+  }
+  return promise;
 }
 
 function watchFiles(testFiles, root, inspectPort) {

test/fixtures/test-runner/dependent.js

@@ -1,3 +1,5 @@
+const test = require('node:test');
 require('./dependency.js');
 import('./dependency.mjs');
 import('data:text/javascript,');
+test('test has ran');

test/parallel/test-runner-watch-mode.mjs

@@ -11,22 +11,25 @@ async function testWatch({ files, fileToUpdate }) {
   const ran2 = util.createDeferredPromise();
   const child = spawn(process.execPath, ['--watch', '--test', '--no-warnings', ...files], { encoding: 'utf8' });
   let stdout = '';
+
   child.stdout.on('data', (data) => {
     stdout += data.toString();
-    if (/ok 2/.test(stdout)) ran1.resolve();
-    if (/ok 3/.test(stdout)) ran2.resolve();
+    const matches = stdout.match(/test has ran/g);
+    if (matches?.length >= 1) ran1.resolve();
+    if (matches?.length >= 2) ran2.resolve();
   });
 
   await ran1.promise;
-  writeFileSync(fileToUpdate, readFileSync(fileToUpdate, 'utf8'));
+  const interval = setInterval(() => writeFileSync(fileToUpdate, readFileSync(fileToUpdate, 'utf8')), 50);
   await ran2.promise;
+  clearInterval(interval);
   child.kill();
 }
 
 describe('test runner watch mode', () => {
   it('should run tests repeatedly', async () => {
     const file1 = fixtures.path('test-runner/index.test.js');
-    const file2 = fixtures.path('test-runner/subdir/subdir_test.js');
+    const file2 = fixtures.path('test-runner/dependent.js');
     await testWatch({ files: [file1, file2], fileToUpdate: file2 });
   });