Changed one assertion to use matchers instead of size and index check.

PiperOrigin-RevId: 437311298
diff --git a/quic/core/quic_buffered_packet_store_test.cc b/quic/core/quic_buffered_packet_store_test.cc
index 8886d6d..301d641 100644
--- a/quic/core/quic_buffered_packet_store_test.cc
+++ b/quic/core/quic_buffered_packet_store_test.cc
@@ -30,6 +30,7 @@
 using BufferedPacket = QuicBufferedPacketStore::BufferedPacket;
 using BufferedPacketList = QuicBufferedPacketStore::BufferedPacketList;
 using EnqueuePacketResult = QuicBufferedPacketStore::EnqueuePacketResult;
+using ::testing::ElementsAre;
 class QuicBufferedPacketStoreVisitor
     : public QuicBufferedPacketStore::VisitorInterface {
  public:
@@ -490,8 +491,7 @@
       connection_id, valid_version_, *packets[1], &alpns, &sni,
       &resumption_attempted, &early_data_attempted));
 
-  ASSERT_EQ(alpns.size(), 1u);
-  EXPECT_EQ(alpns[0], AlpnForVersion(valid_version_));
+  EXPECT_THAT(alpns, ElementsAre(AlpnForVersion(valid_version_)));
   EXPECT_EQ(sni, TestHostname());
 
   EXPECT_FALSE(resumption_attempted);