clio/tests/unit/rpc/handlers/NFTSellOffersTests.cpp

#include "data/Types.hpp"
#include "rpc/Errors.hpp"
#include "rpc/common/AnyHandler.hpp"
#include "rpc/common/Types.hpp"
#include "rpc/handlers/NFTSellOffers.hpp"
#include "util/HandlerBaseTestFixture.hpp"
#include "util/TestObject.hpp"

#include <boost/asio/spawn.hpp>
#include <boost/json/parse.hpp>
#include <boost/json/value_to.hpp>
#include <fmt/format.h>
#include <gmock/gmock.h>
#include <gtest/gtest.h>
#include <xrpl/basics/base_uint.h>
#include <xrpl/protocol/Indexes.h>
#include <xrpl/protocol/LedgerHeader.h>
#include <xrpl/protocol/STObject.h>

#include <optional>
#include <string>
#include <vector>

using namespace rpc;
using namespace data;
namespace json = boost::json;
using namespace testing;

namespace {

constexpr auto kAccount = "rf1BiGeXwwQoi8Z2ueFYTEXSwuJYfV2Jpn";
constexpr auto kLedgerHash = "4BC50C9B0D8515D3EAAE1E74B29A95804346C491EE1A95BF25E4AAB854A6A652";
constexpr auto kNftId = "00010000A7CAD27B688D14BA1A9FA5366554D6ADCF9CE0875B974D9F00000004";
constexpr auto kIndex1 = "E6DBAFC99223B42257915A63DFC6B0C032D4070F9A574B255AD97466726FC321";
constexpr auto kIndex2 = "E6DBAFC99223B42257915A63DFC6B0C032D4070F9A574B255AD97466726FC322";

}  // namespace

struct RPCNFTSellOffersHandlerTest : HandlerBaseTest {
    RPCNFTSellOffersHandlerTest()
    {
        backend_->setRange(10, 30);
    }
};

TEST_F(RPCNFTSellOffersHandlerTest, LimitNotInt)
{
    runSpawn([this](boost::asio::yield_context yield) {
        auto const handler = AnyHandler{NFTSellOffersHandler{backend_}};
        auto const input = json::parse(
            fmt::format(
                R"JSON({{
                    "nft_id": "{}",
                    "limit": "xxx"
                }})JSON",
                kNftId
            )
        );
        auto const output = handler.process(input, Context{.yield = yield});
        ASSERT_FALSE(output);

        auto const err = rpc::makeError(output.result.error());
        EXPECT_EQ(err.at("error").as_string(), "invalidParams");
    });
}

TEST_F(RPCNFTSellOffersHandlerTest, LimitNegative)
{
    runSpawn([this](boost::asio::yield_context yield) {
        auto const handler = AnyHandler{NFTSellOffersHandler{backend_}};
        auto const input = json::parse(
            fmt::format(
                R"JSON({{
                    "nft_id": "{}",
                    "limit": -1
                }})JSON",
                kNftId
            )
        );
        auto const output = handler.process(input, Context{.yield = yield});
        ASSERT_FALSE(output);

        auto const err = rpc::makeError(output.result.error());
        EXPECT_EQ(err.at("error").as_string(), "invalidParams");
    });
}

TEST_F(RPCNFTSellOffersHandlerTest, LimitZero)
{
    runSpawn([this](boost::asio::yield_context yield) {
        auto const handler = AnyHandler{NFTSellOffersHandler{backend_}};
        auto const input = json::parse(
            fmt::format(
                R"JSON({{
                    "nft_id": "{}",
                    "limit": 0
                }})JSON",
                kNftId
            )
        );
        auto const output = handler.process(input, Context{.yield = yield});
        ASSERT_FALSE(output);

        auto const err = rpc::makeError(output.result.error());
        EXPECT_EQ(err.at("error").as_string(), "invalidParams");
    });
}

TEST_F(RPCNFTSellOffersHandlerTest, NonHexLedgerHash)
{
    runSpawn([this](boost::asio::yield_context yield) {
        auto const handler = AnyHandler{NFTSellOffersHandler{backend_}};
        auto const input = json::parse(
            fmt::format(
                R"JSON({{
                    "nft_id": "{}",
                    "ledger_hash": "xxx"
                }})JSON",
                kNftId
            )
        );
        auto const output = handler.process(input, Context{.yield = yield});
        ASSERT_FALSE(output);

        auto const err = rpc::makeError(output.result.error());
        EXPECT_EQ(err.at("error").as_string(), "invalidParams");
        EXPECT_EQ(err.at("error_message").as_string(), "ledger_hashMalformed");
    });
}

TEST_F(RPCNFTSellOffersHandlerTest, NonStringLedgerHash)
{
    runSpawn([this](boost::asio::yield_context yield) {
        auto const handler = AnyHandler{NFTSellOffersHandler{backend_}};
        auto const input = json::parse(
            fmt::format(
                R"JSON({{
                    "nft_id": "{}",
                    "ledger_hash": 123
                }})JSON",
                kNftId
            )
        );
        auto const output = handler.process(input, Context{.yield = yield});
        ASSERT_FALSE(output);

        auto const err = rpc::makeError(output.result.error());
        EXPECT_EQ(err.at("error").as_string(), "invalidParams");
        EXPECT_EQ(err.at("error_message").as_string(), "ledger_hashNotString");
    });
}

TEST_F(RPCNFTSellOffersHandlerTest, InvalidLedgerIndexString)
{
    runSpawn([this](boost::asio::yield_context yield) {
        auto const handler = AnyHandler{NFTSellOffersHandler{backend_}};
        auto const input = json::parse(
            fmt::format(
                R"JSON({{
                    "nft_id": "{}",
                    "ledger_index": "notvalidated"
                }})JSON",
                kNftId
            )
        );
        auto const output = handler.process(input, Context{.yield = yield});
        ASSERT_FALSE(output);

        auto const err = rpc::makeError(output.result.error());
        EXPECT_EQ(err.at("error").as_string(), "invalidParams");
        EXPECT_EQ(err.at("error_message").as_string(), "ledgerIndexMalformed");
    });
}

// error case: nft_id invalid format, length is incorrect
TEST_F(RPCNFTSellOffersHandlerTest, NFTIDInvalidFormat)
{
    runSpawn([this](boost::asio::yield_context yield) {
        auto const handler = AnyHandler{NFTSellOffersHandler{backend_}};
        auto const input = json::parse(R"JSON({
            "nft_id": "00080000B4F4AFC5FBCBD76873F18006173D2193467D3EE7"
        })JSON");
        auto const output = handler.process(input, Context{.yield = yield});
        ASSERT_FALSE(output);
        auto const err = rpc::makeError(output.result.error());
        EXPECT_EQ(err.at("error").as_string(), "invalidParams");
        EXPECT_EQ(err.at("error_message").as_string(), "nft_idMalformed");
    });
}

// error case: nft_id invalid format
TEST_F(RPCNFTSellOffersHandlerTest, NFTIDNotString)
{
    runSpawn([this](boost::asio::yield_context yield) {
        auto const handler = AnyHandler{NFTSellOffersHandler{backend_}};
        auto const input = json::parse(R"JSON({
            "nft_id": 12
        })JSON");
        auto const output = handler.process(input, Context{.yield = yield});
        ASSERT_FALSE(output);

        auto const err = rpc::makeError(output.result.error());
        EXPECT_EQ(err.at("error").as_string(), "invalidParams");
        EXPECT_EQ(err.at("error_message").as_string(), "nft_idNotString");
    });
}

// error case ledger non exist via hash
TEST_F(RPCNFTSellOffersHandlerTest, NonExistLedgerViaLedgerHash)
{
    // mock fetchLedgerByHash return empty
    ON_CALL(*backend_, fetchLedgerByHash(ripple::uint256{kLedgerHash}, _))
        .WillByDefault(Return(std::optional<ripple::LedgerHeader>{}));
    EXPECT_CALL(*backend_, fetchLedgerByHash).Times(1);

    auto const input = json::parse(
        fmt::format(
            R"JSON({{
                "nft_id": "{}",
                "ledger_hash": "{}"
            }})JSON",
            kNftId,
            kLedgerHash
        )
    );
    runSpawn([&, this](boost::asio::yield_context yield) {
        auto const handler = AnyHandler{NFTSellOffersHandler{backend_}};
        auto const output = handler.process(input, Context{.yield = yield});
        ASSERT_FALSE(output);

        auto const err = rpc::makeError(output.result.error());
        EXPECT_EQ(err.at("error").as_string(), "lgrNotFound");
        EXPECT_EQ(err.at("error_message").as_string(), "ledgerNotFound");
    });
}

// error case ledger non exist via index
TEST_F(RPCNFTSellOffersHandlerTest, NonExistLedgerViaLedgerIndex)
{
    // mock fetchLedgerBySequence return empty
    ON_CALL(*backend_, fetchLedgerBySequence)
        .WillByDefault(Return(std::optional<ripple::LedgerHeader>{}));
    EXPECT_CALL(*backend_, fetchLedgerBySequence).Times(1);
    auto const input = json::parse(
        fmt::format(
            R"JSON({{
                "nft_id": "{}",
                "ledger_index": "4"
            }})JSON",
            kNftId
        )
    );
    runSpawn([&, this](boost::asio::yield_context yield) {
        auto const handler = AnyHandler{NFTSellOffersHandler{backend_}};
        auto const output = handler.process(input, Context{.yield = yield});
        ASSERT_FALSE(output);
        auto const err = rpc::makeError(output.result.error());
        EXPECT_EQ(err.at("error").as_string(), "lgrNotFound");
        EXPECT_EQ(err.at("error_message").as_string(), "ledgerNotFound");
    });
}

// error case ledger > max seq via hash
// idk why this case will happen in reality
TEST_F(RPCNFTSellOffersHandlerTest, NonExistLedgerViaLedgerHash2)
{
    // mock fetchLedgerByHash return ledger but seq is 31 > 30
    auto ledgerHeader = createLedgerHeader(kLedgerHash, 31);
    ON_CALL(*backend_, fetchLedgerByHash(ripple::uint256{kLedgerHash}, _))
        .WillByDefault(Return(ledgerHeader));
    EXPECT_CALL(*backend_, fetchLedgerByHash).Times(1);
    auto const input = json::parse(
        fmt::format(
            R"JSON({{
                "nft_id": "{}",
                "ledger_hash": "{}"
            }})JSON",
            kNftId,
            kLedgerHash
        )
    );
    runSpawn([&, this](boost::asio::yield_context yield) {
        auto const handler = AnyHandler{NFTSellOffersHandler{backend_}};
        auto const output = handler.process(input, Context{.yield = yield});
        ASSERT_FALSE(output);
        auto const err = rpc::makeError(output.result.error());
        EXPECT_EQ(err.at("error").as_string(), "lgrNotFound");
        EXPECT_EQ(err.at("error_message").as_string(), "ledgerNotFound");
    });
}

// error case ledger > max seq via index
TEST_F(RPCNFTSellOffersHandlerTest, NonExistLedgerViaLedgerIndex2)
{
    // no need to check from db, call fetchLedgerBySequence 0 time
    // differ from previous logic
    EXPECT_CALL(*backend_, fetchLedgerBySequence).Times(0);
    auto const input = json::parse(
        fmt::format(
            R"JSON({{
                "nft_id": "{}",
                "ledger_index": "31"
            }})JSON",
            kNftId
        )
    );
    runSpawn([&, this](boost::asio::yield_context yield) {
        auto const handler = AnyHandler{NFTSellOffersHandler{backend_}};
        auto const output = handler.process(input, Context{.yield = yield});
        ASSERT_FALSE(output);
        auto const err = rpc::makeError(output.result.error());
        EXPECT_EQ(err.at("error").as_string(), "lgrNotFound");
        EXPECT_EQ(err.at("error_message").as_string(), "ledgerNotFound");
    });
}

// error case when nft is not found
TEST_F(RPCNFTSellOffersHandlerTest, NoNFT)
{
    auto ledgerHeader = createLedgerHeader(kLedgerHash, 30);
    ON_CALL(*backend_, fetchLedgerByHash(ripple::uint256{kLedgerHash}, _))
        .WillByDefault(Return(ledgerHeader));
    EXPECT_CALL(*backend_, fetchLedgerByHash).Times(1);
    ON_CALL(*backend_, doFetchLedgerObject).WillByDefault(Return(std::nullopt));
    EXPECT_CALL(*backend_, doFetchLedgerObject).Times(1);
    auto const input = json::parse(
        fmt::format(
            R"JSON({{
                "nft_id": "{}",
                "ledger_hash": "{}"
            }})JSON",
            kNftId,
            kLedgerHash
        )
    );
    runSpawn([&, this](boost::asio::yield_context yield) {
        auto const handler = AnyHandler{NFTSellOffersHandler{backend_}};
        auto const output = handler.process(input, Context{.yield = yield});
        ASSERT_FALSE(output);
        auto const err = rpc::makeError(output.result.error());
        EXPECT_EQ(err.at("error").as_string(), "objectNotFound");
        EXPECT_EQ(err.at("error_message").as_string(), "notFound");
    });
}

TEST_F(RPCNFTSellOffersHandlerTest, MarkerNotString)
{
    runSpawn([this](auto yield) {
        auto const handler = AnyHandler{NFTSellOffersHandler{backend_}};
        auto const input = json::parse(
            fmt::format(
                R"JSON({{
                    "nft_id": "{}",
                    "marker": 9
                }})JSON",
                kNftId
            )
        );
        auto const output = handler.process(input, Context{yield});
        ASSERT_FALSE(output);

        auto const err = rpc::makeError(output.result.error());
        EXPECT_EQ(err.at("error").as_string(), "invalidParams");
        EXPECT_EQ(err.at("error_message").as_string(), "markerNotString");
    });
}

// error case : invalid marker
// marker format in this RPC is a hex-string of a ripple::uint256.
TEST_F(RPCNFTSellOffersHandlerTest, InvalidMarker)
{
    runSpawn([this](auto yield) {
        auto const handler = AnyHandler{NFTSellOffersHandler{backend_}};
        auto const input = json::parse(
            fmt::format(
                R"JSON({{
                    "nft_id": "{}",
                    "marker": "123invalid"
                }})JSON",
                kNftId
            )
        );
        auto const output = handler.process(input, Context{yield});
        ASSERT_FALSE(output);

        auto const err = rpc::makeError(output.result.error());
        EXPECT_EQ(err.at("error").as_string(), "invalidParams");
        EXPECT_EQ(err.at("error_message").as_string(), "markerMalformed");
    });
    runSpawn([&, this](auto yield) {
        auto const handler = AnyHandler{NFTSellOffersHandler{backend_}};
        auto const input = json::parse(
            fmt::format(
                R"JSON({{
                    "nft_id": "{}",
                    "marker": 250
                }})JSON",
                kNftId
            )
        );
        auto const output = handler.process(input, Context{yield});
        ASSERT_FALSE(output);

        auto const err = rpc::makeError(output.result.error());
        EXPECT_EQ(err.at("error").as_string(), "invalidParams");
    });
}

// normal case when only provide nft_id
TEST_F(RPCNFTSellOffersHandlerTest, DefaultParameters)
{
    static constexpr auto kCorrectOutput = R"JSON({
        "nft_id": "00010000A7CAD27B688D14BA1A9FA5366554D6ADCF9CE0875B974D9F00000004",
        "validated": true,
        "offers": [
            {
                "nft_offer_index": "E6DBAFC99223B42257915A63DFC6B0C032D4070F9A574B255AD97466726FC321",
                "flags": 0,
                "owner": "rf1BiGeXwwQoi8Z2ueFYTEXSwuJYfV2Jpn",
                "amount": "123"
            },
            {
                "nft_offer_index": "E6DBAFC99223B42257915A63DFC6B0C032D4070F9A574B255AD97466726FC322",
                "flags": 0,
                "owner": "rf1BiGeXwwQoi8Z2ueFYTEXSwuJYfV2Jpn",
                "amount": "123"
            }
        ]
    })JSON";

    auto ledgerHeader = createLedgerHeader(kLedgerHash, 30);
    ON_CALL(*backend_, fetchLedgerBySequence).WillByDefault(Return(ledgerHeader));
    EXPECT_CALL(*backend_, fetchLedgerBySequence).Times(1);

    // return owner index containing 2 indexes
    auto const directory = ripple::keylet::nft_sells(ripple::uint256{kNftId});
    auto const ownerDir =
        createOwnerDirLedgerObject({ripple::uint256{kIndex1}, ripple::uint256{kIndex2}}, kIndex1);

    ON_CALL(*backend_, doFetchLedgerObject(directory.key, testing::_, testing::_))
        .WillByDefault(Return(ownerDir.getSerializer().peekData()));
    EXPECT_CALL(*backend_, doFetchLedgerObject(directory.key, testing::_, testing::_)).Times(2);

    // return two nft sell offers
    std::vector<Blob> bbs;
    auto const offer = createNftSellOffer(kNftId, kAccount);
    bbs.push_back(offer.getSerializer().peekData());
    bbs.push_back(offer.getSerializer().peekData());
    ON_CALL(*backend_, doFetchLedgerObjects).WillByDefault(Return(bbs));
    EXPECT_CALL(*backend_, doFetchLedgerObjects).Times(1);

    auto const input = json::parse(
        fmt::format(
            R"JSON({{
                "nft_id": "{}"
            }})JSON",
            kNftId
        )
    );
    runSpawn([&, this](auto yield) {
        auto handler = AnyHandler{NFTSellOffersHandler{this->backend_}};
        auto const output = handler.process(input, Context{yield});

        ASSERT_TRUE(output);
        EXPECT_EQ(json::parse(kCorrectOutput), *output.result);
    });
}

// normal case when provided with nft_id and limit
TEST_F(RPCNFTSellOffersHandlerTest, MultipleResultsWithMarkerAndLimitOutput)
{
    auto ledgerHeader = createLedgerHeader(kLedgerHash, 30);
    ON_CALL(*backend_, fetchLedgerBySequence).WillByDefault(Return(ledgerHeader));
    EXPECT_CALL(*backend_, fetchLedgerBySequence).Times(1);

    // return owner index
    std::vector<ripple::uint256> indexes;
    std::vector<Blob> bbs;
    auto repetitions = 500;
    auto const offer = createNftSellOffer(kNftId, kAccount);
    auto idx = ripple::uint256{kIndex1};
    while ((repetitions--) != 0) {
        indexes.push_back(idx++);
        bbs.push_back(offer.getSerializer().peekData());
    }
    ripple::STObject const ownerDir = createOwnerDirLedgerObject(indexes, kIndex1);

    ON_CALL(*backend_, doFetchLedgerObject)
        .WillByDefault(Return(ownerDir.getSerializer().peekData()));
    EXPECT_CALL(*backend_, doFetchLedgerObject).Times(2);

    ON_CALL(*backend_, doFetchLedgerObjects).WillByDefault(Return(bbs));
    EXPECT_CALL(*backend_, doFetchLedgerObjects).Times(1);

    auto const input = json::parse(
        fmt::format(
            R"JSON({{
                "nft_id": "{}",
                "limit": 50
            }})JSON",
            kNftId
        )
    );
    runSpawn([&, this](auto yield) {
        auto handler = AnyHandler{NFTSellOffersHandler{this->backend_}};
        auto const output = handler.process(input, Context{yield});

        ASSERT_TRUE(output);
        EXPECT_EQ(output.result->at("offers").as_array().size(), 50);
        EXPECT_EQ(output.result->at("limit").as_uint64(), 50);
        EXPECT_EQ(
            boost::json::value_to<std::string>(output.result->at("marker")),
            "E6DBAFC99223B42257915A63DFC6B0C032D4070F9A574B255AD97466726FC353"
        );
    });
}

// normal case when provided with nft_id, limit and marker
TEST_F(RPCNFTSellOffersHandlerTest, ResultsForInputWithMarkerAndLimit)
{
    auto ledgerHeader = createLedgerHeader(kLedgerHash, 30);
    ON_CALL(*backend_, fetchLedgerBySequence).WillByDefault(Return(ledgerHeader));
    EXPECT_CALL(*backend_, fetchLedgerBySequence).Times(1);

    // return owner index
    std::vector<ripple::uint256> indexes;
    std::vector<Blob> bbs;
    auto repetitions = 500;
    auto const offer = createNftSellOffer(kNftId, kAccount);
    auto idx = ripple::uint256{kIndex1};
    while ((repetitions--) != 0) {
        indexes.push_back(idx++);
        bbs.push_back(offer.getSerializer().peekData());
    }
    ripple::STObject const ownerDir = createOwnerDirLedgerObject(indexes, kIndex1);
    auto const cursorSellOffer = createNftSellOffer(kNftId, kAccount);

    // first is nft offer object
    auto const cursor =
        ripple::uint256{"E6DBAFC99223B42257915A63DFC6B0C032D4070F9A574B255AD97466726FC353"};
    auto const first = ripple::keylet::nftoffer(cursor);
    ON_CALL(*backend_, doFetchLedgerObject(first.key, testing::_, testing::_))
        .WillByDefault(Return(cursorSellOffer.getSerializer().peekData()));
    EXPECT_CALL(*backend_, doFetchLedgerObject(first.key, testing::_, testing::_)).Times(1);

    auto const directory = ripple::keylet::nft_sells(ripple::uint256{kNftId});
    auto const startHint = 0ul;  // offer node is hardcoded to 0ul
    auto const secondKey = ripple::keylet::page(directory, startHint).key;
    ON_CALL(*backend_, doFetchLedgerObject(secondKey, testing::_, testing::_))
        .WillByDefault(Return(ownerDir.getSerializer().peekData()));
    EXPECT_CALL(*backend_, doFetchLedgerObject(secondKey, testing::_, testing::_)).Times(3);

    ON_CALL(*backend_, doFetchLedgerObjects).WillByDefault(Return(bbs));
    EXPECT_CALL(*backend_, doFetchLedgerObjects).Times(1);

    auto const input = json::parse(
        fmt::format(
            R"JSON({{
                "nft_id": "{}",
                "marker": "E6DBAFC99223B42257915A63DFC6B0C032D4070F9A574B255AD97466726FC353",
                "limit": 50
            }})JSON",
            kNftId
        )
    );
    runSpawn([&, this](auto yield) {
        auto handler = AnyHandler{NFTSellOffersHandler{this->backend_}};
        auto const output = handler.process(input, Context{yield});

        ASSERT_TRUE(output);
        EXPECT_EQ(output.result->at("offers").as_array().size(), 50);
        EXPECT_EQ(output.result->at("limit").as_uint64(), 50);
        // marker also progressed by 50
        EXPECT_EQ(
            boost::json::value_to<std::string>(output.result->at("marker")),
            "E6DBAFC99223B42257915A63DFC6B0C032D4070F9A574B255AD97466726FC385"
        );
    });
}

// normal case when provided with nft_id, limit and marker
// nothing left after reading remaining 50 entries
TEST_F(RPCNFTSellOffersHandlerTest, ResultsWithoutMarkerForInputWithMarkerAndLimit)
{
    auto ledgerHeader = createLedgerHeader(kLedgerHash, 30);
    ON_CALL(*backend_, fetchLedgerBySequence).WillByDefault(Return(ledgerHeader));
    EXPECT_CALL(*backend_, fetchLedgerBySequence).Times(3);

    // return owner index
    std::vector<ripple::uint256> indexes;
    std::vector<Blob> bbs;
    auto repetitions = 100;
    auto const offer = createNftSellOffer(kNftId, kAccount);
    auto idx = ripple::uint256{kIndex1};
    while ((repetitions--) != 0) {
        indexes.push_back(idx++);
        bbs.push_back(offer.getSerializer().peekData());
    }
    ripple::STObject const ownerDir = createOwnerDirLedgerObject(indexes, kIndex1);
    auto const cursorSellOffer = createNftSellOffer(kNftId, kAccount);

    // first is nft offer object
    auto const cursor =
        ripple::uint256{"E6DBAFC99223B42257915A63DFC6B0C032D4070F9A574B255AD97466726FC353"};
    auto const first = ripple::keylet::nftoffer(cursor);
    ON_CALL(*backend_, doFetchLedgerObject(first.key, testing::_, testing::_))
        .WillByDefault(Return(cursorSellOffer.getSerializer().peekData()));
    EXPECT_CALL(*backend_, doFetchLedgerObject(first.key, testing::_, testing::_)).Times(1);

    auto const directory = ripple::keylet::nft_sells(ripple::uint256{kNftId});
    auto const startHint = 0ul;  // offer node is hardcoded to 0ul
    auto const secondKey = ripple::keylet::page(directory, startHint).key;
    ON_CALL(*backend_, doFetchLedgerObject(secondKey, testing::_, testing::_))
        .WillByDefault(Return(ownerDir.getSerializer().peekData()));
    EXPECT_CALL(*backend_, doFetchLedgerObject(secondKey, testing::_, testing::_)).Times(7);

    ON_CALL(*backend_, doFetchLedgerObjects).WillByDefault(Return(bbs));
    EXPECT_CALL(*backend_, doFetchLedgerObjects).Times(3);

    runSpawn([&, this](auto yield) {
        auto handler = AnyHandler{NFTSellOffersHandler{this->backend_}};
        auto const input = json::parse(
            fmt::format(
                R"JSON({{
                    "nft_id": "{}",
                    "marker": "E6DBAFC99223B42257915A63DFC6B0C032D4070F9A574B255AD97466726FC353",
                    "limit": 50
                }})JSON",
                kNftId
            )
        );
        auto const output = handler.process(input, Context{yield});

        ASSERT_TRUE(output);
        EXPECT_EQ(output.result->at("offers").as_array().size(), 50);
        // no marker/limit to output - we read all items already
        EXPECT_FALSE(output.result->as_object().contains("limit"));
        EXPECT_FALSE(output.result->as_object().contains("marker"));
    });

    runSpawn([this](auto yield) {
        auto const handler = AnyHandler{NFTSellOffersHandler{backend_}};
        auto const input = json::parse(
            fmt::format(
                R"JSON({{
                    "nft_id": "{}",
                    "limit": 49
                }})JSON",
                kNftId
            )
        );
        auto const output = handler.process(input, Context{yield});
        ASSERT_TRUE(output);  // todo: check limit?
    });

    runSpawn([this](auto yield) {
        auto const handler = AnyHandler{NFTSellOffersHandler{backend_}};
        auto const input = json::parse(
            fmt::format(
                R"JSON({{
                    "nft_id": "{}",
                    "limit": 501
                }})JSON",
                kNftId
            )
        );
        auto const output = handler.process(input, Context{yield});
        ASSERT_TRUE(output);  // todo: check limit?
    });
}

TEST_F(RPCNFTSellOffersHandlerTest, LimitLessThanMin)
{
    auto ledgerHeader = createLedgerHeader(kLedgerHash, 30);
    ON_CALL(*backend_, fetchLedgerBySequence).WillByDefault(Return(ledgerHeader));
    EXPECT_CALL(*backend_, fetchLedgerBySequence).Times(1);

    // return owner index containing 2 indexes
    auto const directory = ripple::keylet::nft_sells(ripple::uint256{kNftId});
    auto const ownerDir = createOwnerDirLedgerObject(
        std::vector{NFTSellOffersHandler::kLimitMin + 1, ripple::uint256{kIndex1}}, kIndex1
    );

    ON_CALL(*backend_, doFetchLedgerObject(directory.key, testing::_, testing::_))
        .WillByDefault(Return(ownerDir.getSerializer().peekData()));
    EXPECT_CALL(*backend_, doFetchLedgerObject(directory.key, testing::_, testing::_)).Times(2);

    // return two nft buy offers
    std::vector<Blob> bbs;
    auto const offer = createNftSellOffer(kNftId, kAccount);
    bbs.reserve(NFTSellOffersHandler::kLimitMin + 1);
    for (auto i = 0; i < NFTSellOffersHandler::kLimitMin + 1; i++)
        bbs.push_back(offer.getSerializer().peekData());
    ON_CALL(*backend_, doFetchLedgerObjects).WillByDefault(Return(bbs));
    EXPECT_CALL(*backend_, doFetchLedgerObjects).Times(1);

    auto const input = json::parse(
        fmt::format(
            R"JSON({{
                "nft_id": "{}",
                "limit": {}
            }})JSON",
            kNftId,
            NFTSellOffersHandler::kLimitMin - 1
        )
    );
    runSpawn([&, this](auto yield) {
        auto handler = AnyHandler{NFTSellOffersHandler{this->backend_}};
        auto const output = handler.process(input, Context{yield});

        ASSERT_TRUE(output);
        EXPECT_EQ(output.result->at("offers").as_array().size(), NFTSellOffersHandler::kLimitMin);
        EXPECT_EQ(output.result->at("limit").as_uint64(), NFTSellOffersHandler::kLimitMin);
    });
}

TEST_F(RPCNFTSellOffersHandlerTest, LimitMoreThanMax)
{
    auto ledgerHeader = createLedgerHeader(kLedgerHash, 30);
    ON_CALL(*backend_, fetchLedgerBySequence).WillByDefault(Return(ledgerHeader));
    EXPECT_CALL(*backend_, fetchLedgerBySequence).Times(1);

    // return owner index containing 2 indexes
    auto const directory = ripple::keylet::nft_sells(ripple::uint256{kNftId});
    auto const ownerDir = createOwnerDirLedgerObject(
        std::vector{NFTSellOffersHandler::kLimitMax + 1, ripple::uint256{kIndex1}}, kIndex1
    );

    ON_CALL(*backend_, doFetchLedgerObject(directory.key, testing::_, testing::_))
        .WillByDefault(Return(ownerDir.getSerializer().peekData()));
    EXPECT_CALL(*backend_, doFetchLedgerObject(directory.key, testing::_, testing::_)).Times(2);

    // return two nft buy offers
    std::vector<Blob> bbs;
    auto const offer = createNftSellOffer(kNftId, kAccount);
    bbs.reserve(NFTSellOffersHandler::kLimitMax + 1);
    for (auto i = 0; i < NFTSellOffersHandler::kLimitMax + 1; i++)
        bbs.push_back(offer.getSerializer().peekData());
    ON_CALL(*backend_, doFetchLedgerObjects).WillByDefault(Return(bbs));
    EXPECT_CALL(*backend_, doFetchLedgerObjects).Times(1);

    auto const input = json::parse(
        fmt::format(
            R"JSON({{
                "nft_id": "{}",
                "limit": {}
            }})JSON",
            kNftId,
            NFTSellOffersHandler::kLimitMax + 1
        )
    );
    runSpawn([&, this](auto yield) {
        auto handler = AnyHandler{NFTSellOffersHandler{this->backend_}};
        auto const output = handler.process(input, Context{yield});

        ASSERT_TRUE(output);
        EXPECT_EQ(output.result->at("offers").as_array().size(), NFTSellOffersHandler::kLimitMax);
        EXPECT_EQ(output.result->at("limit").as_uint64(), NFTSellOffersHandler::kLimitMax);
    });
}