// Copyright (c) 2012-2016 The Bitcoin Core developers
// Copyright (c) 2017-2025 The Bitcoin developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#include <serialize.h>

#include <hash.h>
#include <streams.h>
#include <util/strencodings.h>

#include <test/setup_common.h>

#include <boost/test/unit_test.hpp>

#include <algorithm>
#include <cstdint>
#include <limits>
#include <optional>
#include <string>
#include <string_view>
#include <utility>
#include <vector>

BOOST_FIXTURE_TEST_SUITE(serialize_tests, BasicTestingSetup)

class CSerializeMethodsTestSingle {
protected:
    int intval;
    bool boolval;
    std::string stringval;
    char charstrval[16];
    CTransactionRef txval;

public:
    CSerializeMethodsTestSingle() = default;
    CSerializeMethodsTestSingle(int intvalin, bool boolvalin,
                                std::string stringvalin,
                                const char *charstrvalin,
                                const CTransactionRef &txvalin)
        : intval(intvalin), boolval(boolvalin),
          stringval(std::move(stringvalin)), txval(txvalin) {
        memcpy(charstrval, charstrvalin, sizeof(charstrval));
    }

    SERIALIZE_METHODS(CSerializeMethodsTestSingle, obj) {
        READWRITE(obj.intval);
        READWRITE(obj.boolval);
        READWRITE(obj.stringval);
        READWRITE(obj.charstrval);
        READWRITE(obj.txval);
    }

    bool operator==(const CSerializeMethodsTestSingle &rhs) const {
        return intval == rhs.intval && boolval == rhs.boolval &&
               stringval == rhs.stringval &&
               strcmp(charstrval, rhs.charstrval) == 0 && *txval == *rhs.txval;
    }
};

class CSerializeMethodsTestMany : public CSerializeMethodsTestSingle {
public:
    using CSerializeMethodsTestSingle::CSerializeMethodsTestSingle;

    SERIALIZE_METHODS(CSerializeMethodsTestMany, obj) {
        READWRITE(obj.intval, obj.boolval, obj.stringval, obj.charstrval, obj.txval);
    }
};

BOOST_AUTO_TEST_CASE(sizes) {
    BOOST_CHECK_EQUAL(sizeof(char), GetSerializeSize(char(0)));
    BOOST_CHECK_EQUAL(sizeof(int8_t), GetSerializeSize(int8_t(0)));
    BOOST_CHECK_EQUAL(sizeof(uint8_t), GetSerializeSize(uint8_t(0)));
    BOOST_CHECK_EQUAL(sizeof(int16_t), GetSerializeSize(int16_t(0)));
    BOOST_CHECK_EQUAL(sizeof(uint16_t), GetSerializeSize(uint16_t(0)));
    BOOST_CHECK_EQUAL(sizeof(int32_t), GetSerializeSize(int32_t(0)));
    BOOST_CHECK_EQUAL(sizeof(uint32_t), GetSerializeSize(uint32_t(0)));
    BOOST_CHECK_EQUAL(sizeof(int64_t), GetSerializeSize(int64_t(0)));
    BOOST_CHECK_EQUAL(sizeof(uint64_t), GetSerializeSize(uint64_t(0)));
    BOOST_CHECK_EQUAL(sizeof(float), GetSerializeSize(float(0)));
    BOOST_CHECK_EQUAL(sizeof(double), GetSerializeSize(double(0)));
    // Bool is serialized as char
    BOOST_CHECK_EQUAL(sizeof(char), GetSerializeSize(bool(0)));

    // Sanity-check GetSerializeSize and c++ type matching
    BOOST_CHECK_EQUAL(GetSerializeSize(char(0)), 1U);
    BOOST_CHECK_EQUAL(GetSerializeSize(int8_t(0)), 1U);
    BOOST_CHECK_EQUAL(GetSerializeSize(uint8_t(0)), 1U);
    BOOST_CHECK_EQUAL(GetSerializeSize(int16_t(0)), 2U);
    BOOST_CHECK_EQUAL(GetSerializeSize(uint16_t(0)), 2U);
    BOOST_CHECK_EQUAL(GetSerializeSize(int32_t(0)), 4U);
    BOOST_CHECK_EQUAL(GetSerializeSize(uint32_t(0)), 4U);
    BOOST_CHECK_EQUAL(GetSerializeSize(int64_t(0)), 8U);
    BOOST_CHECK_EQUAL(GetSerializeSize(uint64_t(0)), 8U);
    BOOST_CHECK_EQUAL(GetSerializeSize(float(0)), 4U);
    BOOST_CHECK_EQUAL(GetSerializeSize(double(0)), 8U);
    BOOST_CHECK_EQUAL(GetSerializeSize(bool(0)), 1U);
}

BOOST_AUTO_TEST_CASE(floats_conversion) {
    // Choose values that map unambiguously to binary floating point to avoid
    // rounding issues at the compiler side.
    BOOST_CHECK_EQUAL(ser_uint32_to_float(0x00000000), 0.0F);
    BOOST_CHECK_EQUAL(ser_uint32_to_float(0x3f000000), 0.5F);
    BOOST_CHECK_EQUAL(ser_uint32_to_float(0x3f800000), 1.0F);
    BOOST_CHECK_EQUAL(ser_uint32_to_float(0x40000000), 2.0F);
    BOOST_CHECK_EQUAL(ser_uint32_to_float(0x40800000), 4.0F);
    BOOST_CHECK_EQUAL(ser_uint32_to_float(0x44444444), 785.066650390625F);

    BOOST_CHECK_EQUAL(ser_float_to_uint32(0.0F), 0x00000000U);
    BOOST_CHECK_EQUAL(ser_float_to_uint32(0.5F), 0x3f000000U);
    BOOST_CHECK_EQUAL(ser_float_to_uint32(1.0F), 0x3f800000U);
    BOOST_CHECK_EQUAL(ser_float_to_uint32(2.0F), 0x40000000U);
    BOOST_CHECK_EQUAL(ser_float_to_uint32(4.0F), 0x40800000U);
    BOOST_CHECK_EQUAL(ser_float_to_uint32(785.066650390625F), 0x44444444U);
}

BOOST_AUTO_TEST_CASE(doubles_conversion) {
    // Choose values that map unambiguously to binary floating point to avoid
    // rounding issues at the compiler side.
    BOOST_CHECK_EQUAL(ser_uint64_to_double(0x0000000000000000ULL), 0.0);
    BOOST_CHECK_EQUAL(ser_uint64_to_double(0x3fe0000000000000ULL), 0.5);
    BOOST_CHECK_EQUAL(ser_uint64_to_double(0x3ff0000000000000ULL), 1.0);
    BOOST_CHECK_EQUAL(ser_uint64_to_double(0x4000000000000000ULL), 2.0);
    BOOST_CHECK_EQUAL(ser_uint64_to_double(0x4010000000000000ULL), 4.0);
    BOOST_CHECK_EQUAL(ser_uint64_to_double(0x4088888880000000ULL),
                      785.066650390625);

    BOOST_CHECK_EQUAL(ser_double_to_uint64(0.0), 0x0000000000000000ULL);
    BOOST_CHECK_EQUAL(ser_double_to_uint64(0.5), 0x3fe0000000000000ULL);
    BOOST_CHECK_EQUAL(ser_double_to_uint64(1.0), 0x3ff0000000000000ULL);
    BOOST_CHECK_EQUAL(ser_double_to_uint64(2.0), 0x4000000000000000ULL);
    BOOST_CHECK_EQUAL(ser_double_to_uint64(4.0), 0x4010000000000000ULL);
    BOOST_CHECK_EQUAL(ser_double_to_uint64(785.066650390625),
                      0x4088888880000000ULL);
}
/*
Python code to generate the below hashes:

    def reversed_hex(x):
        return binascii.hexlify(''.join(reversed(x)))
    def dsha256(x):
        return hashlib.sha256(hashlib.sha256(x).digest()).digest()

    reversed_hex(dsha256(''.join(struct.pack('<f', x) for x in range(0,1000))))
== '8e8b4cf3e4df8b332057e3e23af42ebc663b61e0495d5e7e32d85099d7f3fe0c'
    reversed_hex(dsha256(''.join(struct.pack('<d', x) for x in range(0,1000))))
== '43d0c82591953c4eafe114590d392676a01585d25b25d433557f0d7878b23f96'
*/
BOOST_AUTO_TEST_CASE(floats) {
    CDataStream ss(SER_DISK, 0);
    // encode
    for (int i = 0; i < 1000; i++) {
        ss << float(i);
    }
    BOOST_CHECK(Hash(ss) == uint256S("8e8b4cf3e4df8b332057e3e23af42ebc663b61e0495d5e7e32d85099d7f3fe0c"));

    // decode
    for (int i = 0; i < 1000; i++) {
        float j;
        ss >> j;
        BOOST_CHECK_MESSAGE(i == j, "decoded:" << j << " expected:" << i);
    }
}

BOOST_AUTO_TEST_CASE(doubles) {
    CDataStream ss(SER_DISK, 0);
    // encode
    for (int i = 0; i < 1000; i++) {
        ss << double(i);
    }
    BOOST_CHECK(Hash(ss) == uint256S("43d0c82591953c4eafe114590d392676a01585d25b25d433557f0d7878b23f96"));

    // decode
    for (int i = 0; i < 1000; i++) {
        double j;
        ss >> j;
        BOOST_CHECK_MESSAGE(i == j, "decoded:" << j << " expected:" << i);
    }
}

BOOST_AUTO_TEST_CASE(varints) {
    // encode

    CDataStream ss(SER_DISK, 0);
    CDataStream::size_type size = 0;
    for (int i = 0; i < 100000; i++) {
        ss << VARINT_MODE(i, VarIntMode::NONNEGATIVE_SIGNED);
        size +=
            ::GetSerializeSize(VARINT_MODE(i, VarIntMode::NONNEGATIVE_SIGNED));
        BOOST_CHECK(size == ss.size());
    }

    for (uint64_t i = 0; i < 100000000000ULL; i += 999999937) {
        ss << VARINT(i);
        size += ::GetSerializeSize(VARINT(i));
        BOOST_CHECK(size == ss.size());
    }

    // decode
    for (int i = 0; i < 100000; i++) {
        int j = -1;
        ss >> VARINT_MODE(j, VarIntMode::NONNEGATIVE_SIGNED);
        BOOST_CHECK_MESSAGE(i == j, "decoded:" << j << " expected:" << i);
    }

    for (uint64_t i = 0; i < 100000000000ULL; i += 999999937) {
        uint64_t j = std::numeric_limits<uint64_t>::max();
        ss >> VARINT(j);
        BOOST_CHECK_MESSAGE(i == j, "decoded:" << j << " expected:" << i);
    }
}

BOOST_AUTO_TEST_CASE(varints_bitpatterns) {
    CDataStream ss(SER_DISK, 0);
    ss << VARINT_MODE(0, VarIntMode::NONNEGATIVE_SIGNED);
    BOOST_CHECK_EQUAL(HexStr(ss), "00");
    ss.clear();
    ss << VARINT_MODE(0x7f, VarIntMode::NONNEGATIVE_SIGNED);
    BOOST_CHECK_EQUAL(HexStr(ss), "7f");
    ss.clear();
    ss << VARINT_MODE((int8_t)0x7f, VarIntMode::NONNEGATIVE_SIGNED);
    BOOST_CHECK_EQUAL(HexStr(ss), "7f");
    ss.clear();
    ss << VARINT_MODE(0x80, VarIntMode::NONNEGATIVE_SIGNED);
    BOOST_CHECK_EQUAL(HexStr(ss), "8000");
    ss.clear();
    ss << VARINT((uint8_t)0x80);
    BOOST_CHECK_EQUAL(HexStr(ss), "8000");
    ss.clear();
    ss << VARINT_MODE(0x1234, VarIntMode::NONNEGATIVE_SIGNED);
    BOOST_CHECK_EQUAL(HexStr(ss), "a334");
    ss.clear();
    ss << VARINT_MODE((int16_t)0x1234, VarIntMode::NONNEGATIVE_SIGNED);
    BOOST_CHECK_EQUAL(HexStr(ss), "a334");
    ss.clear();
    ss << VARINT_MODE(0xffff, VarIntMode::NONNEGATIVE_SIGNED);
    BOOST_CHECK_EQUAL(HexStr(ss), "82fe7f");
    ss.clear();
    ss << VARINT((uint16_t)0xffff);
    BOOST_CHECK_EQUAL(HexStr(ss), "82fe7f");
    ss.clear();
    ss << VARINT_MODE(0x123456, VarIntMode::NONNEGATIVE_SIGNED);
    BOOST_CHECK_EQUAL(HexStr(ss), "c7e756");
    ss.clear();
    ss << VARINT_MODE((int32_t)0x123456, VarIntMode::NONNEGATIVE_SIGNED);
    BOOST_CHECK_EQUAL(HexStr(ss), "c7e756");
    ss.clear();
    ss << VARINT(0x80123456U);
    BOOST_CHECK_EQUAL(HexStr(ss), "86ffc7e756");
    ss.clear();
    ss << VARINT((uint32_t)0x80123456U);
    BOOST_CHECK_EQUAL(HexStr(ss), "86ffc7e756");
    ss.clear();
    ss << VARINT(0xffffffff);
    BOOST_CHECK_EQUAL(HexStr(ss), "8efefefe7f");
    ss.clear();
    ss << VARINT_MODE(0x7fffffffffffffffLL, VarIntMode::NONNEGATIVE_SIGNED);
    BOOST_CHECK_EQUAL(HexStr(ss), "fefefefefefefefe7f");
    ss.clear();
    ss << VARINT(0xffffffffffffffffULL);
    BOOST_CHECK_EQUAL(HexStr(ss), "80fefefefefefefefe7f");
    ss.clear();
}

static bool isTooLargeException(const std::ios_base::failure &ex) {
    std::ios_base::failure expectedException(
        "ReadCompactSize(): size too large");

    // The string returned by what() can be different for different platforms.
    // Instead of directly comparing the ex.what() with an expected string,
    // create an instance of exception to see if ex.what() matches  the expected
    // explanatory string returned by the exception instance.
    return strcmp(expectedException.what(), ex.what()) == 0;
}

BOOST_AUTO_TEST_CASE(compactsize) {
    CDataStream ss(SER_DISK, 0);
    std::vector<char>::size_type i, j;

    for (i = 1; i <= MAX_SIZE; i *= 2) {
        WriteCompactSize(ss, i - 1);
        WriteCompactSize(ss, i);
    }
    for (i = 1; i <= MAX_SIZE; i *= 2) {
        j = ReadCompactSize(ss);
        BOOST_CHECK_MESSAGE((i - 1) == j,
                            "decoded:" << j << " expected:" << (i - 1));
        j = ReadCompactSize(ss);
        BOOST_CHECK_MESSAGE(i == j, "decoded:" << j << " expected:" << i);
    }

    WriteCompactSize(ss, MAX_SIZE);
    BOOST_CHECK_EQUAL(ReadCompactSize(ss), MAX_SIZE);

    WriteCompactSize(ss, MAX_SIZE + 1);
    BOOST_CHECK_EXCEPTION(ReadCompactSize(ss), std::ios_base::failure,
                          isTooLargeException);

    WriteCompactSize(ss, std::numeric_limits<int64_t>::max());
    BOOST_CHECK_EXCEPTION(ReadCompactSize(ss), std::ios_base::failure,
                          isTooLargeException);

    WriteCompactSize(ss, std::numeric_limits<uint64_t>::max());
    BOOST_CHECK_EXCEPTION(ReadCompactSize(ss), std::ios_base::failure,
                          isTooLargeException);
}

static bool isCanonicalException(const std::ios_base::failure &ex) {
    std::ios_base::failure expectedException("non-canonical ReadCompactSize()");

    // The string returned by what() can be different for different platforms.
    // Instead of directly comparing the ex.what() with an expected string,
    // create an instance of exception to see if ex.what() matches  the expected
    // explanatory string returned by the exception instance.
    return strcmp(expectedException.what(), ex.what()) == 0;
}

BOOST_AUTO_TEST_CASE(vector_bool) {
    std::vector<uint8_t> vec1{1, 0, 0, 1, 1, 1, 0, 0, 0, 0, 1, 0, 0, 1, 1, 0, 0, 0, 1, 1, 1, 1, 0, 1, 0, 0, 1};
    std::vector<bool> vec2{1, 0, 0, 1, 1, 1, 0, 0, 0, 0, 1, 0, 0, 1, 1, 0, 0, 0, 1, 1, 1, 1, 0, 1, 0, 0, 1};

    BOOST_CHECK(vec1 == std::vector<uint8_t>(vec2.begin(), vec2.end()));
    BOOST_CHECK(SerializeHash(vec1) == SerializeHash(vec2));
}

BOOST_AUTO_TEST_CASE(noncanonical) {
    // Write some non-canonical CompactSize encodings, and make sure an
    // exception is thrown when read back.
    CDataStream ss(SER_DISK, 0);
    std::vector<char>::size_type n;

    // zero encoded with three bytes:
    ss.write("\xfd\x00\x00", 3);
    BOOST_CHECK_EXCEPTION(ReadCompactSize(ss), std::ios_base::failure,
                          isCanonicalException);

    // 0xfc encoded with three bytes:
    ss.write("\xfd\xfc\x00", 3);
    BOOST_CHECK_EXCEPTION(ReadCompactSize(ss), std::ios_base::failure,
                          isCanonicalException);

    // 0xfd encoded with three bytes is OK:
    ss.write("\xfd\xfd\x00", 3);
    n = ReadCompactSize(ss);
    BOOST_CHECK(n == 0xfd);

    // zero encoded with five bytes:
    ss.write("\xfe\x00\x00\x00\x00", 5);
    BOOST_CHECK_EXCEPTION(ReadCompactSize(ss), std::ios_base::failure,
                          isCanonicalException);

    // 0xffff encoded with five bytes:
    ss.write("\xfe\xff\xff\x00\x00", 5);
    BOOST_CHECK_EXCEPTION(ReadCompactSize(ss), std::ios_base::failure,
                          isCanonicalException);

    // zero encoded with nine bytes:
    ss.write("\xff\x00\x00\x00\x00\x00\x00\x00\x00", 9);
    BOOST_CHECK_EXCEPTION(ReadCompactSize(ss), std::ios_base::failure,
                          isCanonicalException);

    // 0x01ffffff encoded with nine bytes:
    ss.write("\xff\xff\xff\xff\x01\x00\x00\x00\x00", 9);
    BOOST_CHECK_EXCEPTION(ReadCompactSize(ss), std::ios_base::failure,
                          isCanonicalException);
}

BOOST_AUTO_TEST_CASE(insert_delete) {
    // Test inserting/deleting bytes.
    CDataStream ss(SER_DISK, 0);
    BOOST_CHECK_EQUAL(ss.size(), 0U);

    ss.write("\x00\x01\x02\xff", 4);
    BOOST_CHECK_EQUAL(ss.size(), 4U);

    char c = (char)11;

    // Inserting at beginning/end/middle:
    ss.insert(ss.begin(), c);
    BOOST_CHECK_EQUAL(ss.size(), 5U);
    BOOST_CHECK_EQUAL(ss[0], c);
    BOOST_CHECK_EQUAL(ss[1], 0);

    ss.insert(ss.end(), c);
    BOOST_CHECK_EQUAL(ss.size(), 6U);
    BOOST_CHECK_EQUAL(ss[4], (char)0xff);
    BOOST_CHECK_EQUAL(ss[5], c);

    ss.insert(ss.begin() + 2, c);
    BOOST_CHECK_EQUAL(ss.size(), 7U);
    BOOST_CHECK_EQUAL(ss[2], c);

    // Delete at beginning/end/middle
    ss.erase(ss.begin());
    BOOST_CHECK_EQUAL(ss.size(), 6U);
    BOOST_CHECK_EQUAL(ss[0], 0);

    ss.erase(ss.begin() + ss.size() - 1);
    BOOST_CHECK_EQUAL(ss.size(), 5U);
    BOOST_CHECK_EQUAL(ss[4], (char)0xff);

    ss.erase(ss.begin() + 1);
    BOOST_CHECK_EQUAL(ss.size(), 4U);
    BOOST_CHECK_EQUAL(ss[0], 0);
    BOOST_CHECK_EQUAL(ss[1], 1);
    BOOST_CHECK_EQUAL(ss[2], 2);
    BOOST_CHECK_EQUAL(ss[3], (char)0xff);

    // Make sure GetAndClear does the right thing:
    CDataStream::vector_type d;
    ss.GetAndClear(d);
    BOOST_CHECK_EQUAL(ss.size(), 0U);
}

BOOST_AUTO_TEST_CASE(class_methods) {
    int intval(100);
    bool boolval(true);
    std::string stringval("testing");
    const char charstrval[16] = "testing charstr";
    CMutableTransaction txval;
    CTransactionRef tx_ref{MakeTransactionRef(txval)};
    CSerializeMethodsTestSingle methodtest1(intval, boolval, stringval,
                                            charstrval, tx_ref);
    CSerializeMethodsTestMany methodtest2(intval, boolval, stringval,
                                          charstrval, tx_ref);
    CSerializeMethodsTestSingle methodtest3;
    CSerializeMethodsTestMany methodtest4;
    CDataStream ss(SER_DISK, PROTOCOL_VERSION);
    BOOST_CHECK(methodtest1 == methodtest2);
    ss << methodtest1;
    ss >> methodtest4;
    ss << methodtest2;
    ss >> methodtest3;
    BOOST_CHECK(methodtest1 == methodtest2);
    BOOST_CHECK(methodtest2 == methodtest3);
    BOOST_CHECK(methodtest3 == methodtest4);

    CDataStream ss2(SER_DISK, PROTOCOL_VERSION, intval, boolval, stringval,
                    charstrval, txval);
    ss2 >> methodtest3;
    BOOST_CHECK(methodtest3 == methodtest4);
}

BOOST_AUTO_TEST_CASE(optional) {
    const int intval(424242);
    const bool boolval(true);
    const std::string stringval("testing testing 123");
    const char charstrval[16] = "testing charstr";
    const auto txhex = "010000000175ecb0496f9152b9598a5cfeccfaa9f20c0cd4cb540558ea5e61fb2421ee98f10000000064417c2f08dff"
                       "94a18e4f2394e023aa1bd08d0f75392d753d628a3c59225cd0a9ef52b80fe4447c44ba2dc61e0ad4336800745ea3f34"
                       "5827e1d7e907ab33ccfee1a74121024eeb7a4eee3d31ae61208cb3e6a742e4dbf65ea39b2759844f076052bc1766f9f"
                       "effffff0196939800000000001976a9142d2c8cf85c532e09a3ad0d16dd45d0fdff66025088ac76300200";
    CMutableTransaction txval;
    VectorReader(SER_DISK, PROTOCOL_VERSION, ParseHex(txhex), 0) >> txval;
    CTransactionRef tx_ref{MakeTransactionRef(txval)};
    const CSerializeMethodsTestSingle obj(intval, boolval, stringval, charstrval, tx_ref);
    std::optional<CSerializeMethodsTestSingle> optObj, optObj2;

    // Check ser/deser round-trip of an optional that has a value
    optObj = obj;
    BOOST_CHECK(optObj.has_value());
    BOOST_CHECK(!optObj2.has_value());
    (CDataStream(SER_DISK, PROTOCOL_VERSION) << optObj) >> optObj2;
    BOOST_CHECK(optObj == optObj2);
    BOOST_CHECK(optObj.has_value());
    BOOST_CHECK(optObj2.has_value());
    BOOST_CHECK(*optObj2 == obj);

    // Check ser/deser round-trip of an optional without a value
    optObj.reset();
    BOOST_CHECK(!optObj.has_value());
    BOOST_CHECK(optObj2.has_value());
    (CDataStream(SER_DISK, PROTOCOL_VERSION) << optObj) >> optObj2;
    BOOST_CHECK(optObj == optObj2);
    BOOST_CHECK(!optObj.has_value());
    BOOST_CHECK(!optObj2.has_value());

    // Manually build the buffer, format is: 1/0 char to indicate has_value, then the embedded object
    std::vector<uint8_t> buf;

    CVectorWriter(SER_DISK, PROTOCOL_VERSION, buf, 0) << uint8_t(1) << obj;
    BOOST_CHECK(!buf.empty());
    BOOST_CHECK(!optObj.has_value());
    VectorReader(SER_DISK, PROTOCOL_VERSION, buf, 0) >> optObj;
    BOOST_CHECK(optObj.has_value());
    BOOST_CHECK(*optObj == obj);

    // Do out-of-spec non-zero >1 at beginning of buffer -- should throw
    buf[0] = 2u;
    optObj.reset();
    auto isExpectedMessage = [](const auto &ex) {
        return std::string_view{ex.what()}.find("optional encoding") != std::string_view::npos;
    };
    BOOST_CHECK_EXCEPTION((VectorReader(SER_DISK, PROTOCOL_VERSION, buf, 0) >> optObj),
                          std::ios_base::failure, isExpectedMessage);
    // On this failure mode, optObj should remain unchanged
    BOOST_CHECK(!optObj.has_value());
    // Do it again and verify optObj2 still has its original value even after we got the non-canonical exception
    optObj2 = obj;
    BOOST_CHECK_EXCEPTION((VectorReader(SER_DISK, PROTOCOL_VERSION, buf, 0) >> optObj2),
                          std::ios_base::failure, isExpectedMessage);
    BOOST_CHECK(optObj2.has_value());
    BOOST_CHECK(*optObj2 == obj);

    // Test that 0 at beginning of buffer yields an empty optional
    optObj = obj;
    BOOST_CHECK(optObj.has_value());
    buf[0] = 0u;
    VectorReader vr(SER_DISK, PROTOCOL_VERSION, buf, 0);
    vr >> optObj;
    BOOST_CHECK(!optObj.has_value());
    BOOST_CHECK(!vr.empty()); // has bytes leftover after reading leading 0
}

BOOST_AUTO_TEST_CASE(span) {
    // Test both our custom Span type and std::span types serialize and unserialize properly
    constexpr size_t nBytes = 512u;
    const std::vector<uint8_t> zeroes(nBytes);
    std::vector<uint8_t> randomData = zeroes, tmp = zeroes;
    BOOST_CHECK(randomData == tmp && randomData == zeroes
                && std::all_of(randomData.begin(), randomData.end(), [](const uint8_t x){ return x == 0; }));
    for (size_t i = 0, nb; i < nBytes; i += nb) {
        // fill with random data
        nb = std::min<size_t>(randomData.size() - i, 32u);
        GetRandBytes(randomData.data() + i, nb);
    }
    BOOST_CHECK(randomData != tmp && randomData != zeroes && randomData.size() == tmp.size());

    // Test serializing Span & std::span

    // Ensure serializing a Span just writes the bytes with no leading compactsize
    CVectorWriter(SER_DISK, PROTOCOL_VERSION, tmp, 0) << Span{randomData};
    BOOST_CHECK(randomData == tmp); // result should just be raw bytes
    tmp = zeroes; // clear
    BOOST_CHECK(randomData != tmp);
    // Do same for std::span
    CVectorWriter(SER_DISK, PROTOCOL_VERSION, tmp, 0) << std::span{randomData};
    BOOST_CHECK(randomData == tmp); // result should just be raw bytes
    tmp = zeroes; // clear
    // Repeat the above with a Span<const uint8_t> & std::span<const uint8_t>
    CVectorWriter(SER_DISK, PROTOCOL_VERSION, tmp, 0) << Span{std::as_const(randomData)};
    BOOST_CHECK(randomData == tmp); // result should just be raw bytes
    tmp = zeroes; // clear
    BOOST_CHECK(randomData != tmp);
    // Do same for std::span
    CVectorWriter(SER_DISK, PROTOCOL_VERSION, tmp, 0) << std::span{std::as_const(randomData)};
    BOOST_CHECK(randomData == tmp); // result should just be raw bytes
    tmp = zeroes; // clear


    // Test unserializing Span & std::span

    BOOST_CHECK(randomData != tmp);
    VectorReader(SER_DISK, PROTOCOL_VERSION, randomData, 0) >> Span{tmp};
    BOOST_CHECK(randomData == tmp); // result should just be raw bytes
    tmp = zeroes; // clear
    BOOST_CHECK(randomData != tmp);
    VectorReader(SER_DISK, PROTOCOL_VERSION, randomData, 0) >> std::span{tmp};
    BOOST_CHECK(randomData == tmp); // result should just be raw bytes
    tmp = zeroes; // clear
    BOOST_CHECK(randomData != tmp);


    // Test unserializing into a "view" of a larger writable buffer

    auto Equals = [](const std::span<const uint8_t> &a, const std::span<const uint8_t> &b) {
        return a.size() == b.size() && std::equal(a.begin(), a.end(), b.begin());
    };
    const std::vector<uint8_t> partial(randomData.begin(), randomData.begin() + randomData.size() / 2);
    BOOST_CHECK(Equals(std::span{partial}, std::span{randomData}.first(partial.size())));
    BOOST_CHECK(!Equals(std::span{partial}, std::span{tmp}.first(partial.size())));
    // Unserialize a Span equal to the size of "partial", but from 'randomData' as the source
    VectorReader(SER_DISK, PROTOCOL_VERSION, randomData, 0) >> Span{tmp}.first(partial.size()); // Span
    BOOST_CHECK(partial != tmp);
    BOOST_CHECK(randomData != tmp);
    BOOST_CHECK(Equals(std::span{partial}, std::span{tmp}.first(partial.size())));
    tmp = zeroes;
    BOOST_CHECK(!Equals(std::span{partial}, std::span{tmp}.first(partial.size())));
    // Do same for std::span
    VectorReader(SER_DISK, PROTOCOL_VERSION, randomData, 0) >> std::span{tmp}.first(partial.size()); // std::span
    BOOST_CHECK(partial != tmp);
    BOOST_CHECK(randomData != tmp);
    BOOST_CHECK(Equals(std::span{partial}, std::span{tmp}.first(partial.size())));
    tmp = zeroes;
    BOOST_CHECK(!Equals(std::span{partial}, std::span{tmp}.first(partial.size())));
}

BOOST_AUTO_TEST_SUITE_END()
