test: fix flaky test-http2-settings-flood

The test is unreliable on some Windows platforms in its current form.
Make it more robust by using `setInterval()` to repeat the flooding
until an error is triggered.

Fixes: nodejs#18251

PR-URL: nodejs#19349
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Anatoli Papirovski <apapirovski@mac.com>

test/sequential/sequential.status

@@ -12,7 +12,6 @@ test-inspector-bindings               : PASS, FLAKY
 test-inspector-debug-end              : PASS, FLAKY
 test-inspector-async-hook-setup-at-signal:  PASS, FLAKY
 test-http2-ping-flood                 : PASS, FLAKY
-test-http2-settings-flood             : PASS, FLAKY
 
 [$system==linux]
 

test/sequential/test-http2-settings-flood.js

@@ -4,8 +4,10 @@ const common = require('../common');
 if (!common.hasCrypto)
   common.skip('missing crypto');
 
+const assert = require('assert');
 const http2 = require('http2');
 const net = require('net');
+
 const http2util = require('../common/http2');
 
 // Test that settings flooding causes the session to be torn down
@@ -14,13 +16,16 @@ const kSettings = new http2util.SettingsFrame();
 
 const server = http2.createServer();
 
+let interval;
+
 server.on('stream', common.mustNotCall());
 server.on('session', common.mustCall((session) => {
-  session.on('error', common.expectsError({
-    code: 'ERR_HTTP2_ERROR',
-    message:
-      'Flooding was detected in this HTTP/2 session, and it must be closed'
-  }));
+  session.on('error', (e) => {
+    assert.strictEqual(e.code, 'ERR_HTTP2_ERROR');
+    assert(e.message.includes('Flooding was detected'));
+    clearInterval(interval);
+  });
+
   session.on('close', common.mustCall(() => {
     server.close();
   }));
@@ -30,18 +35,18 @@ server.listen(0, common.mustCall(() => {
   const client = net.connect(server.address().port);
 
   // nghttp2 uses a limit of 10000 items in it's outbound queue.
-  // If this number is exceeded, a flooding error is raised. Set
-  // this lim higher to account for the ones that nghttp2 is
-  // successfully able to respond to.
+  // If this number is exceeded, a flooding error is raised.
   // TODO(jasnell): Unfortunately, this test is inherently flaky because
   // it is entirely dependent on how quickly the server is able to handle
   // the inbound frames and whether those just happen to overflow nghttp2's
   // outbound queue. The threshold at which the flood error occurs can vary
   // from one system to another, and from one test run to another.
   client.on('connect', common.mustCall(() => {
     client.write(http2util.kClientMagic, () => {
-      for (let n = 0; n < 35000; n++)
-        client.write(kSettings.data);
+      interval = setInterval(() => {
+        for (let n = 0; n < 10000; n++)
+          client.write(kSettings.data);
+      }, 1);
     });
   }));