test: simplify test-tls-alert

Avoid the process 'exit' event handler and use execFile instead of
manual stream operations.
Refs: #46751
PR-URL: #46805
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

Author: tniessen

test/parallel/test-tls-alert.js

@@ -28,12 +28,10 @@ if (!common.opensslCli)
 common.skip('node compiled without OpenSSL CLI.');
 
 constassert=require('assert');
-const{spawn}=require('child_process');
+const{execFile}=require('child_process');
 consttls=require('tls');
 constfixtures=require('../common/fixtures');
 
-letsuccess=false;
-
 functionloadPEM(n){
 returnfixtures.readKey(`${n}.pem`);
 }
@@ -42,21 +40,13 @@ const server = tls.Server({
 secureProtocol: 'TLSv1_2_server_method',
 key: loadPEM('agent2-key'),
 cert: loadPEM('agent2-cert')
-},null).listen(0,function(){
+},null).listen(0,common.mustCall(()=>{
 constargs=['s_client','-quiet','-tls1_1',
-'-connect',`127.0.0.1:${this.address().port}`];
+'-connect',`127.0.0.1:${server.address().port}`];
 
-constclient=spawn(common.opensslCli,args);
-letout='';
-client.stderr.setEncoding('utf8');
-client.stderr.on('data',function(d){
-out+=d;
-if(/SSLalertnumber70/.test(out)){
-success=true;
-server.close();
-}
-});
-});
-process.on('exit',function(){
-assert(success);
-});
+execFile(common.opensslCli,args,common.mustCall((err,_,stderr)=>{
+assert.strictEqual(err.code,1);
+assert.match(stderr,/SSLalertnumber70/);
+server.close();
+}));
+}));