esphome/tests/components/pn532/pn532_test.cpp

#include <gtest/gtest.h>

#include <array>
#include <deque>
#include <span>

#include "esphome/components/pn532/pn532.h"

namespace esphome::pn532 {

namespace {

// Stands in for the bus: acknowledges every command and answers with queued response payloads.
class FakePN532 : public PN532 {
 public:
  using PN532::auth_mifare_classic_block_;
  using PN532::read_mifare_ultralight_bytes_;
  using PN532::read_mifare_classic_block_;
  using PN532::write_command_;
  using PN532::write_mifare_classic_block_;
  using PN532::write_mifare_ultralight_page_;

  std::deque<std::vector<uint8_t>> responses;
  std::vector<std::vector<uint8_t>> written;

 protected:
  bool is_read_ready() override { return true; }
  bool write_data(std::span<const uint8_t> data) override {
    this->written.emplace_back(data.begin(), data.end());
    return true;
  }
  // only used for ACK frames; index 0 is the I2C status byte
  bool read_data(PN532Frame &data, size_t len) override {
    data = {0x01, 0x00, 0x00, 0xFF, 0x00, 0xFF, 0x00};
    return true;
  }
  bool read_response(uint8_t command, PN532Frame &data) override {
    if (this->responses.empty())
      return false;
    data.assign(this->responses.front().begin(), this->responses.front().end());
    this->responses.pop_front();
    return true;
  }
};

std::vector<uint8_t> bytes_of(std::span<const uint8_t> bytes) { return {bytes.begin(), bytes.end()}; }

// Extracts the command bytes (after TFI) from a normal information frame
std::vector<uint8_t> frame_data(const std::vector<uint8_t> &frame) {
  // preamble, start code (2), LEN, LCS, TFI, data..., DCS, postamble
  return std::vector<uint8_t>(frame.begin() + 6, frame.end() - 2);
}

}  // namespace

TEST(PN532TagType, FromSelRes) {
  EXPECT_EQ(tag_type_from_sel_res(0x08), nfc::TAG_TYPE_MIFARE_CLASSIC);  // Classic 1K
  EXPECT_EQ(tag_type_from_sel_res(0x18), nfc::TAG_TYPE_MIFARE_CLASSIC);  // Classic 4K
  EXPECT_EQ(tag_type_from_sel_res(0x09), nfc::TAG_TYPE_MIFARE_CLASSIC);  // Mini
  EXPECT_EQ(tag_type_from_sel_res(0x01), nfc::TAG_TYPE_MIFARE_CLASSIC);  // TNP3xxx
  EXPECT_EQ(tag_type_from_sel_res(0x00), nfc::TAG_TYPE_2);               // Ultralight / NTAG
  EXPECT_EQ(tag_type_from_sel_res(0x20), nfc::TAG_TYPE_4);               // ISO-DEP (phones, DESFire)
  EXPECT_EQ(tag_type_from_sel_res(0x40), nfc::TAG_TYPE_UNKNOWN);
}

// The frame wraps the command in preamble, start code, LEN, LCS, TFI, DCS and postamble (UM0701-02, 6.2.1.1).
TEST(PN532Frame, WrapsCommand) {
  FakePN532 pn532;
  ASSERT_TRUE(pn532.write_command_({0x4A, 0x01, 0x00}));
  ASSERT_EQ(pn532.written.size(), 1u);
  EXPECT_EQ(pn532.written[0], (std::vector<uint8_t>{0x00, 0x00, 0xFF, 0x04, 0xFC, 0xD4, 0x4A, 0x01, 0x00, 0xE1, 0x00}));
}

// A command that cannot fit a normal information frame is refused rather than truncated.
TEST(PN532Frame, RejectsOversizedCommand) {
  FakePN532 pn532;
  std::array<uint8_t, PN532_FRAME_MAX_DATA_SIZE + 1> too_long{};
  EXPECT_FALSE(pn532.write_command_(too_long));
  EXPECT_TRUE(pn532.written.empty());
  EXPECT_TRUE(pn532.write_command_(std::span<const uint8_t>(too_long).first(PN532_FRAME_MAX_DATA_SIZE)));
  ASSERT_EQ(pn532.written.size(), 1u);
  EXPECT_EQ(pn532.written[0].size(), PN532_FRAME_MAX_DATA_SIZE + 8);
}

// A failed write (status byte other than 0x00) must be reported as a failure.
TEST(PN532Mifare, ClassicWriteChecksStatus) {
  FakePN532 pn532;
  const uint8_t block[16] = {};
  pn532.responses.push_back({0x14});  // authentication error
  EXPECT_FALSE(pn532.write_mifare_classic_block_(4, block));
  pn532.responses.push_back({0x00});
  EXPECT_TRUE(pn532.write_mifare_classic_block_(4, block));
}

TEST(PN532Mifare, UltralightWriteChecksStatus) {
  FakePN532 pn532;
  const uint8_t page[4] = {};
  pn532.responses.push_back({0x01});  // timeout
  EXPECT_FALSE(pn532.write_mifare_ultralight_page_(4, page));
  pn532.responses.push_back({0x00});
  EXPECT_TRUE(pn532.write_mifare_ultralight_page_(4, page));
}

TEST(PN532Mifare, ClassicReadRejectsBadResponses) {
  FakePN532 pn532;
  MifareReadData data{};
  pn532.responses.emplace_back();  // empty response
  EXPECT_FALSE(pn532.read_mifare_classic_block_(4, data));
  pn532.responses.push_back({0x00, 0x01, 0x02});  // short block
  EXPECT_FALSE(pn532.read_mifare_classic_block_(4, data));

  std::vector<uint8_t> good(17, 0xAB);
  good[0] = 0x00;
  pn532.responses.push_back(good);
  EXPECT_TRUE(pn532.read_mifare_classic_block_(4, data));
  EXPECT_EQ(bytes_of(data), std::vector<uint8_t>(16, 0xAB));
}

// The NDEF TLV is type 0x03, a one-byte length below 255 (three bytes otherwise), the message, terminator 0xFE,
// then zero padding out to the requested length.
TEST(PN532Ndef, FillsTlv) {
  FixedVector<uint8_t> buffer;
  const std::array<uint8_t, 3> message = {0xD1, 0x01, 0x02};
  nfc::fill_ndef_tlv(message, 8, buffer);
  EXPECT_EQ(bytes_of(std::span<const uint8_t>(buffer)),
            (std::vector<uint8_t>{0x03, 0x03, 0xD1, 0x01, 0x02, 0xFE, 0x00, 0x00}));

  std::vector<uint8_t> long_message(300, 0xAA);
  nfc::fill_ndef_tlv(long_message, 320, buffer);
  ASSERT_EQ(buffer.size(), 320u);
  EXPECT_EQ(buffer[0], 0x03);
  EXPECT_EQ(buffer[1], 0xFF);
  EXPECT_EQ(buffer[2], 0x01);  // 300 = 0x012C
  EXPECT_EQ(buffer[3], 0x2C);
  EXPECT_EQ(buffer[4], 0xAA);
  EXPECT_EQ(buffer[303], 0xAA);
  EXPECT_EQ(buffer[304], 0xFE);
  EXPECT_EQ(buffer[319], 0x00);
}

// Authentication carries exactly 4 UID bytes: the last 4 of a 7-byte UID.
TEST(PN532Mifare, AuthSendsFourUidBytes) {
  FakePN532 pn532;
  nfc::NfcTagUid uid = {0x04, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66};
  pn532.responses.push_back({0x00});
  EXPECT_TRUE(pn532.auth_mifare_classic_block_(uid, 4, nfc::MIFARE_CMD_AUTH_A, nfc::NDEF_KEY));
  ASSERT_EQ(pn532.written.size(), 1u);
  const auto cmd = frame_data(pn532.written[0]);
  // InDataExchange, Tg, Cmd, Addr, key (6), UID (4)
  ASSERT_EQ(cmd.size(), 14u);
  EXPECT_EQ(std::vector<uint8_t>(cmd.end() - 4, cmd.end()), (std::vector<uint8_t>{0x33, 0x44, 0x55, 0x66}));
}

// Reads in 16-byte chunks, keeps only the bytes asked for, and advances 4 pages per READ.
TEST(PN532Mifare, UltralightReadTrimsLastChunk) {
  FakePN532 pn532;
  std::vector<uint8_t> first(17), second(17);
  first[0] = second[0] = 0x00;  // status
  for (uint8_t i = 0; i < 16; i++) {
    first[i + 1] = i;
    second[i + 1] = 0x10 + i;
  }
  pn532.responses.push_back(first);
  pn532.responses.push_back(second);

  UltralightReadBuffer data;
  ASSERT_TRUE(pn532.read_mifare_ultralight_bytes_(4, 20, data));
  ASSERT_EQ(data.size(), 20u);
  EXPECT_EQ(data[15], 15);
  EXPECT_EQ(data[16], 0x10);
  EXPECT_EQ(data[19], 0x13);

  ASSERT_EQ(pn532.written.size(), 2u);
  EXPECT_EQ(frame_data(pn532.written[0]).back(), 4);  // READ page 4
  EXPECT_EQ(frame_data(pn532.written[1]).back(), 8);  // then page 8
}

TEST(PN532Mifare, UltralightReadRejectsBadResponses) {
  FakePN532 pn532;
  UltralightReadBuffer data;
  pn532.responses.push_back({0x00, 0x01, 0x02});  // short response
  EXPECT_FALSE(pn532.read_mifare_ultralight_bytes_(4, 16, data));

  std::vector<uint8_t> failed(17, 0x00);
  failed[0] = 0x01;  // timeout status
  pn532.responses.push_back(failed);
  data.clear();
  EXPECT_FALSE(pn532.read_mifare_ultralight_bytes_(4, 16, data));
}

}  // namespace esphome::pn532