test: fix flaky http-chunk-extensions-limit test

Replace the setInterval with a queueMicrotask to make test less flaky.

Fixes: nodejs#51883

test/parallel/test-http-chunk-extensions-limit.js

@@ -5,6 +5,11 @@ const http = require('http');
 const net = require('net');
 const assert = require('assert');
 
+// The maximum http chunk extension size is set in `src/node_http_parser.cc`.
+// These tests assert that once the extension size is reached, an HTTP 413
+// response is returned.
+// Currently, the max size is set to 16KiB (16384).
+
 // Verify that chunk extensions are limited in size when sent all together.
 {
   const server = http.createServer((req, res) => {
@@ -17,7 +22,8 @@ const assert = require('assert');
   });
 
   server.listen(0, () => {
-    const sock = net.connect(server.address().port);
+    const port = server.address().port;
+    const sock = net.connect(port);
     let data = '';
 
     sock.on('data', (chunk) => data += chunk.toString('utf-8'));
@@ -29,15 +35,17 @@ const assert = require('assert');
 
     sock.end('' +
       'GET / HTTP/1.1\r\n' +
-      'Host: localhost:8080\r\n' +
+      `Host: localhost:${port}\r\n` +
       'Transfer-Encoding: chunked\r\n\r\n' +
-      '2;' + 'A'.repeat(20000) + '=bar\r\nAA\r\n' +
-      '0\r\n\r\n'
+      '2;' + 'a'.repeat(17000) + '\r\n' + // Chunk size + chunk ext + CRLF
+      'AA\r\n' + // Chunk data
+      '0\r\n' + // Last chunk
+      '\r\n' // End of http message
     );
   });
 }
 
-// Verify that chunk extensions are limited in size when sent in intervals.
+// Verify that chunk extensions are limited in size when sent in parts
 {
   const server = http.createServer((req, res) => {
     req.on('end', () => {
@@ -49,24 +57,10 @@ const assert = require('assert');
   });
 
   server.listen(0, () => {
-    const sock = net.connect(server.address().port);
-    let remaining = 20000;
+    const port = server.address().port;
+    const sock = net.connect(port);
     let data = '';
 
-    const interval = setInterval(
-      () => {
-        if (remaining > 0) {
-          sock.write('A'.repeat(1000));
-        } else {
-          sock.write('=bar\r\nAA\r\n0\r\n\r\n');
-          clearInterval(interval);
-        }
-
-        remaining -= 1000;
-      },
-      common.platformTimeout(20),
-    ).unref();
-
     sock.on('data', (chunk) => data += chunk.toString('utf-8'));
 
     sock.on('end', common.mustCall(function() {
@@ -76,10 +70,20 @@ const assert = require('assert');
 
     sock.write('' +
     'GET / HTTP/1.1\r\n' +
-    'Host: localhost:8080\r\n' +
+    `Host: localhost:${port}\r\n` +
     'Transfer-Encoding: chunked\r\n\r\n' +
-    '2;'
+    '2;' // Chunk size + start of chunk-extension
     );
+
+    sock.write('A'.repeat(8500)); // Write half of the chunk-extension
+
+    queueMicrotask(() => {
+      sock.write('A'.repeat(8500) + '\r\n' + // Remaining half of the chunk-extension
+      'AA\r\n' + // Chunk data
+      '0\r\n' + // Last chunk
+      '\r\n' // End of http message
+      );
+    });
   });
 }
 
@@ -95,7 +99,8 @@ const assert = require('assert');
   });
 
   server.listen(0, () => {
-    const sock = net.connect(server.address().port);
+    const port = server.address().port;
+    const sock = net.connect(port);
     let data = '';
 
     sock.on('data', (chunk) => data += chunk.toString('utf-8'));
@@ -120,7 +125,7 @@ const assert = require('assert');
 
     sock.end('' +
       'GET / HTTP/1.1\r\n' +
-      'Host: localhost:8080\r\n' +
+      `Host: localhost:${port}\r\n` +
       'Transfer-Encoding: chunked\r\n\r\n' +
       '2;' + 'A'.repeat(10000) + '=bar\r\nAA\r\n' +
       '2;' + 'A'.repeat(10000) + '=bar\r\nAA\r\n' +