Add VersionOfIndex() to quic_protocol.h

net/quic/core/quic_protocol_test.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "net/quic/core/quic_protocol.h"
 
 #include <sstream>
 
 #include "base/stl_util.h"
 #include "net/quic/core/quic_flags.h"
@@ skipping 296 matching lines @@
   EXPECT_EQ(FilterSupportedVersions(QuicSupportedVersions()),
             manager.GetSupportedVersions());
   FLAGS_quic_enable_version_35 = true;
   FLAGS_quic_enable_version_36 = true;
   EXPECT_EQ(FilterSupportedVersions(QuicSupportedVersions()),
             manager.GetSupportedVersions());
   EXPECT_EQ(QUIC_VERSION_36, manager.GetSupportedVersions()[0]);
   EXPECT_EQ(QUIC_VERSION_35, manager.GetSupportedVersions()[1]);
 }
 
+TEST(QuicProtocolTest, LookUpVersionByIndex) {
+  QuicVersionVector all_versions = {
+      QUIC_VERSION_30, QUIC_VERSION_31, QUIC_VERSION_32, QUIC_VERSION_33,
+      QUIC_VERSION_34, QUIC_VERSION_35, QUIC_VERSION_36};
+  int version_count = all_versions.size();
+  for (int i = -5; i <= version_count + 1; ++i) {
+    if (i >= 0 && i < version_count) {
+      EXPECT_EQ(all_versions[i], VersionOfIndex(all_versions, i)[0]);
+    } else {
+      EXPECT_EQ(QUIC_VERSION_UNSUPPORTED, VersionOfIndex(all_versions, i)[0]);
+    }
+  }
+}
+
 // Tests that a queue contains the expected data after calls to Add().
 TEST(PacketNumberQueueTest, AddRange) {
   PacketNumberQueue queue;
   queue.Add(1, 51);
   queue.Add(53);
 
   EXPECT_FALSE(queue.Contains(0));
   for (int i = 1; i < 51; ++i) {
     EXPECT_TRUE(queue.Contains(i));
   }
@@ skipping 109 matching lines @@
   EXPECT_EQ(2u, queue.NumIntervals());
   EXPECT_TRUE(queue.Contains(10));
   EXPECT_TRUE(queue.Contains(11));
   EXPECT_TRUE(queue.Contains(20));
   EXPECT_TRUE(queue.Contains(21));
 }
 
 }  // namespace
 }  // namespace test
 }  // namespace net