Add FIDO U2F message and packet classes

device/u2f/u2f_message_unittest.cc

+// Copyright 2016 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 "device/u2f/u2f_message.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+class U2fMessageTest : public testing::Test {};
+
+// Packets should be 64 bytes + 1 report ID byte
+TEST_F(U2fMessageTest, TestPacketSize) {
+  uint8_t channel_id[4] = {5, 6, 7, 8};
+  std::vector<uint8_t> data;
+
+  scoped_refptr<device::U2fPacket> init_packet(
+      new device::U2fInitPacket(channel_id, 0, data, data.size()));
+  ASSERT_EQ(init_packet->GetBuffer()->size(), 65);
+
+  scoped_refptr<device::U2fPacket> cont_packet(
+      new device::U2fContPacket(channel_id, 0, data));
+  ASSERT_EQ(init_packet->GetBuffer()->size(), 65);

[Reilly Grant (use Gerrit), 2016/11/30 20:53:47]

cont_packet?

[Casey Piper, 2016/11/30 22:05:46]

Done.

+}
+
+/*
+ * U2f Init Packets are of the format:
+ * Byte 0:    0
+ * Byte 1-4:  Channel ID
+ * Byte 5:    Command byte
+ * Byte 6-7:  Big Endian size of data
+ * Byte 8-n:  Data block
+ *
+ * Remaining buffer is padded with 0
+ */
+TEST_F(U2fMessageTest, TestPacketData) {
+  uint8_t channel_id[4] = {5, 6, 7, 8};
+  std::vector<uint8_t> data{10, 11};
+  uint8_t cmd = 0x88;

[Reilly Grant (use Gerrit), 2016/11/30 20:53:47]

CMD_WINK?

[Casey Piper, 2016/11/30 22:05:46]

I'll add a static cast here to add clarity. My intention is to make packets
agnostic of command types (since they are currently defined as U2fMessage
constructs, rather than packet constructs).

+  scoped_refptr<device::U2fPacket> init_packet(
+      new device::U2fInitPacket(channel_id, cmd, data, data.size()));
+  int index = 0;
+
+  ASSERT_EQ(init_packet->GetBuffer()->data()[index++], 0);
+  ASSERT_EQ(init_packet->GetBuffer()->data()[index++], channel_id[0]);
+  ASSERT_EQ(init_packet->GetBuffer()->data()[index++], channel_id[1]);
+  ASSERT_EQ(init_packet->GetBuffer()->data()[index++], channel_id[2]);
+  ASSERT_EQ(init_packet->GetBuffer()->data()[index++], channel_id[3]);
+  ASSERT_EQ(init_packet->GetBuffer()->data()[index++], (char)cmd);

[Reilly Grant (use Gerrit), 2016/11/30 20:53:47]

This cast shouldn't be necessary if it wasn't for channel_id[0].

[Casey Piper, 2016/11/30 22:05:46]

Weirdly, the test will fail if I don't have the cast here:
Value of: cmd
  Actual: '\x88' (136)
Expected: init_packet->GetBuffer()->data()[index++]
Which is: '\x88' (136)

[Reilly Grant (use Gerrit), 2016/11/30 22:18:53]

Ah, right, they both get converted to an int for the comparison and -8 (chars
are signed) != 136. This is why uint8_t is better than char. Unfortunately it's
what IOBuffer is stuck with for the time being.

+
+  ASSERT_EQ(init_packet->GetBuffer()->data()[index++],
+            (char)(data.size() >> 8));
+  ASSERT_EQ(init_packet->GetBuffer()->data()[index++],
+            (char)(data.size() & 0xff));
+  ASSERT_EQ(init_packet->GetBuffer()->data()[index++], data.at(0));
+  ASSERT_EQ(init_packet->GetBuffer()->data()[index++], data.at(1));
+  for (; index < init_packet->GetBuffer()->size(); index++) {
+    ASSERT_EQ(init_packet->GetBuffer()->data()[index], 0);
+  }

[Reilly Grant (use Gerrit), 2016/11/30 20:53:47]

Just use this loop for all the elements in the array. Add this to the end of the
ASSERT_EQ to help debugging:

ASSERT_EQ(...) << "mismatch at index " << index;

[Casey Piper, 2016/11/30 22:05:46]

Can you clarify what you mean in the first sentence?

[Reilly Grant (use Gerrit), 2016/11/30 22:18:53]

My mistake. I forgot that data.size() != init_packet->GetBuffer()->size().

+}
+
+TEST_F(U2fMessageTest, TestMessagePartioning) {
+  uint8_t channel_id[4] = {1, 1, 2, 3};
+  std::vector<uint8_t> data(device::U2fMessage::kInitPacketDataSize + 1);
+  scoped_refptr<device::U2fMessage> two_packet_message =
+      device::U2fMessage::Create(channel_id, device::U2fMessage::Type::CMD_PING,
+                                 data);
+  ASSERT_EQ(two_packet_message->NumPackets(), 2U);
+
+  data.resize(device::U2fMessage::kInitPacketDataSize);
+  scoped_refptr<device::U2fMessage> one_packet_message =
+      device::U2fMessage::Create(channel_id, device::U2fMessage::Type::CMD_PING,
+                                 data);
+  ASSERT_EQ(one_packet_message->NumPackets(), 1U);
+
+  data.resize(device::U2fMessage::kInitPacketDataSize +
+              device::U2fMessage::kContPacketDataSize + 1);
+  scoped_refptr<device::U2fMessage> three_packet_message =
+      device::U2fMessage::Create(channel_id, device::U2fMessage::Type::CMD_PING,
+                                 data);
+  ASSERT_EQ(three_packet_message->NumPackets(), 3U);
+}
+
+TEST_F(U2fMessageTest, TestMaxSize) {
+  uint8_t channel_id[4] = {0, 1, 2, 3};
+  std::vector<uint8_t> data(device::U2fMessage::kMaxMessageSize + 1);
+  scoped_refptr<device::U2fMessage> oversize_message =
+      device::U2fMessage::Create(channel_id, device::U2fMessage::Type::CMD_PING,
+                                 data);
+  ASSERT_EQ(oversize_message, nullptr);
+}

[Reilly Grant (use Gerrit), 2016/11/30 20:53:47]

General comment about these tests: We try to use EXPECT_FOO instead of
ASSERT_FOO whenever possible because the former doesn't halt the test and can
make it easier to see the full extent of the error. Only ASSERT on things that
would cause the test to crash later.

[Casey Piper, 2016/11/30 22:05:46]

Acknowledged.

[Reilly Grant (use Gerrit), 2016/11/30 22:18:53]

Also, EXPECT_EQ wants the expected value first. Otherwise the errors it prints
sound weird.