test: verify inspector help url works

This commit adds basic functionality testing of the
help URL printed when the inspector starts.

PR-URL: #19887
Refs: #19871
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: Khaidi Chu <i@2333.moe>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: James M Snell <jasnell@gmail.com>

test/internet/test-inspector-help-page.js

@@ -0,0 +1,37 @@
'use strict';
const common = require('../common');

common.skipIfInspectorDisabled();

if (!common.hasCrypto)
  common.skip('missing crypto');

const assert = require('assert');
const https = require('https');
const { spawnSync } = require('child_process');
const child = spawnSync(process.execPath, ['--inspect', '-e', '""']);
const stderr = child.stderr.toString();
const helpUrl = stderr.match(/For help, see: (.+)/)[1];

function check(url, cb) {
  https.get(url, common.mustCall((res) => {
    assert(res.statusCode >= 200 && res.statusCode < 400);

    if (res.statusCode >= 300)
      return check(res.headers.location, cb);

    let result = '';

    res.setEncoding('utf8');
    res.on('data', (data) => {
      result += data;
    });

    res.on('end', common.mustCall(() => {
      assert(/>Debugging Guide</.test(result));
      cb();
    }));
  })).on('error', common.mustNotCall);
}

check(helpUrl, common.mustCall());