test: clean up http-set-trailers

* remove shared state of request counting from each listener by using
callbacks to report test finish. This also fixes slight race condition
where one of the request could finish before the other was taken into
account resulting in ECONNREFUSED due to premature server.close()
* slightly move code for better cohesion
* fix error comment in testHttp10 'Trailer ...' -> 'No trailer ...'
PR-URL: #30522
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Yongsheng Zhang <zyszys98@gmail.com>

Author: lundibundi

test/parallel/test-http-set-trailers.js

@@ -26,91 +26,77 @@ const http = require('http');
 constnet=require('net');
 constutil=require('util');
 
-letoutstanding_reqs=0;
-
-constserver=http.createServer(function(req,res){
-res.writeHead(200,[['content-type','text/plain']]);
-res.addTrailers({'x-foo': 'bar'});
-res.end('stuff\n');
-});
-server.listen(0);
-
-
 // First, we test an HTTP/1.0 request.
-server.on('listening',function(){
-constc=net.createConnection(this.address().port);
-letres_buffer='';
+functiontestHttp10(port,callback){
+constc=net.createConnection(port);
 
 c.setEncoding('utf8');
 
-c.on('connect',function(){
-outstanding_reqs++;
+c.on('connect',()=>{
 c.write('GET / HTTP/1.0\r\n\r\n');
 });
 
-c.on('data',function(chunk){
+letres_buffer='';
+c.on('data',(chunk)=>{
 res_buffer+=chunk;
 });
 
 c.on('end',function(){
 c.end();
 assert.ok(
 !/x-foo/.test(res_buffer),
-`Trailer in HTTP/1.0 response. Response buffer: ${res_buffer}`
+`No trailer in HTTP/1.0 response. Response buffer: ${res_buffer}`
 );
-outstanding_reqs--;
-if(outstanding_reqs===0){
-server.close();
-}
+callback();
 });
-});
+}
 
 // Now, we test an HTTP/1.1 request.
-server.on('listening',function(){
-constc=net.createConnection(this.address().port);
-letres_buffer='';
-lettid;
+functiontestHttp11(port,callback){
+constc=net.createConnection(port);
 
 c.setEncoding('utf8');
 
+lettid;
 c.on('connect',function(){
-outstanding_reqs++;
 c.write('GET / HTTP/1.1\r\n\r\n');
 tid=setTimeout(common.mustNotCall(),2000,'Couldn\'t find last chunk.');
 });
 
+letres_buffer='';
 c.on('data',function(chunk){
 res_buffer+=chunk;
 if(/0\r\n/.test(res_buffer)){// got the end.
-outstanding_reqs--;
 clearTimeout(tid);
 assert.ok(
 /0\r\nx-foo:bar\r\n\r\n$/.test(res_buffer),
 `No trailer in HTTP/1.1 response. Response buffer: ${res_buffer}`
 );
-if(outstanding_reqs===0){
-server.close();
-}
+callback();
 }
 });
-});
+}
 
 // Now, see if the client sees the trailers.
-server.on('listening',function(){
-http.get({
-port: this.address().port,
-path: '/hello',
-headers: {}
-},function(res){
+functiontestClientTrailers(port,callback){
+http.get({ port,path: '/hello',headers: {}},(res)=>{
 res.on('end',function(){
 assert.ok('x-foo'inres.trailers,
 `${util.inspect(res.trailers)} misses the 'x-foo' property`);
-outstanding_reqs--;
-if(outstanding_reqs===0){
-server.close();
-}
+callback();
 });
 res.resume();
 });
-outstanding_reqs++;
+}
+
+constserver=http.createServer((req,res)=>{
+res.writeHead(200,[['content-type','text/plain']]);
+res.addTrailers({'x-foo': 'bar'});
+res.end('stuff\n');
+});
+server.listen(0,()=>{
+Promise.all([testHttp10,testHttp11,testClientTrailers]
+.map(util.promisify)
+.map((f)=>f(server.address().port)))
+.then(()=>server.close());
 });