test_runner: print info when test restarts

When using spec reporter and running test in watch mode, print an info
message containing the current datetime when tests restart.
Fixes: #57206
PR-URL: #61160
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Moshe Atlow <moshe@atlow.co.il>

Author: Xstoudi

lib/internal/test_runner/reporter/spec.js

@@ -5,6 +5,8 @@ const {
  ArrayPrototypePush,
  ArrayPrototypeShift,
  ArrayPrototypeUnshift,
+ Date,
+ DatePrototypeToLocaleString,
 }=primordials;
 constassert=require('assert');
 constTransform=require('internal/streams/transform');
@@ -101,6 +103,9 @@ class SpecReporter extends Transform {
 if(data.file===undefined){
 returnthis.#formatFailedTestResults();
 }
+break;
+case'test:watch:restarted':
+return`\nRestarted at ${DatePrototypeToLocaleString(newDate())}\n`;
 }
 }
 _transform({ type, data },encoding,callback){

test/test-runner/test-output-spec-reporter-watch-restart.mjs

@@ -0,0 +1,18 @@
+import'../common/index.mjs';
+import{specasSpecReporter}from'node:test/reporters';
+importassertfrom'node:assert';
+
+constreporter=newSpecReporter();
+letoutput='';
+
+reporter.on('data',(chunk)=>{
+output+=chunk;
+});
+
+reporter.write({
+type: 'test:watch:restarted',
+});
+
+reporter.end();
+
+assert.match(output,/Restartedat.+/);