From 438c84460d6ed2dc085c407b05f15eed9e97d608 Mon Sep 17 00:00:00 2001
From: Nick Brown <nickbrow@google.com>
Date: Thu, 17 Mar 2022 16:47:32 -0700
Subject: [PATCH] Poll for POLLERR before validating ICMP error

...since ICMP errors are returned asynchronously. This also matches the
behavior of existing tests.

PiperOrigin-RevId: 435484650
---
 test/syscalls/linux/udp_socket.cc | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/test/syscalls/linux/udp_socket.cc b/test/syscalls/linux/udp_socket.cc
index f126467c0..a870efa53 100644
--- a/test/syscalls/linux/udp_socket.cc
+++ b/test/syscalls/linux/udp_socket.cc
@@ -382,6 +382,11 @@ TEST_P(UdpSocketTest, ConnectWriteToInvalidPort) {
   ASSERT_THAT(sendto(sock_.get(), buf, sizeof(buf), 0, addr, addrlen_),
               SyscallSucceedsWithValue(sizeof(buf)));
 
+  // Poll to make sure we get the ICMP error back.
+  constexpr int kTimeout = 1000;
+  struct pollfd pfd = {sock_.get(), POLLERR, 0};
+  ASSERT_THAT(RetryEINTR(poll)(&pfd, 1, kTimeout), SyscallSucceedsWithValue(1));
+
   // Now verify that we got an ICMP error back of ECONNREFUSED.
   int err;
   socklen_t optlen = sizeof(err);