clio/tests/unit/util/StrandedPriorityQueueTests.cpp

//------------------------------------------------------------------------------
/*
    This file is part of clio: https://github.com/XRPLF/clio
    Copyright (c) 2025, the clio developers.

    Permission to use, copy, modify, and distribute this software for any
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    ACTION  OF  CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
    OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
//==============================================================================

#include "util/StrandedPriorityQueue.hpp"
#include "util/async/AnyExecutionContext.hpp"
#include "util/async/AnyOperation.hpp"
#include "util/async/context/BasicExecutionContext.hpp"

#include <gtest/gtest.h>

#include <atomic>
#include <chrono>
#include <cstdint>
#include <thread>
#include <unordered_set>
#include <vector>

using namespace util;

namespace {

struct TestData {
    uint32_t seq;

    auto
    operator<=>(TestData const&) const = default;
};

}  // namespace

TEST(StrandedPriorityQueueTests, DefaultPriority)
{
    util::async::CoroExecutionContext ctx;
    StrandedPriorityQueue<TestData> queue{ctx.makeStrand()};

    for (auto i = 0u; i < 100u; ++i) {
        EXPECT_TRUE(queue.enqueue(TestData{.seq = i}));
    }

    EXPECT_FALSE(queue.empty());

    auto next = 99u;
    while (auto maybeValue = queue.dequeue()) {
        EXPECT_EQ(maybeValue->seq, next--);
    }

    EXPECT_TRUE(queue.empty());
}

TEST(StrandedPriorityQueueTests, CustomPriority)
{
    struct Comp {
        [[nodiscard]] bool
        operator()(TestData const& lhs, TestData const& rhs) const noexcept
        {
            return lhs.seq > rhs.seq;
        }
    };

    util::async::CoroExecutionContext ctx;
    StrandedPriorityQueue<TestData, Comp> queue{ctx.makeStrand()};

    for (auto i = 0u; i < 100u; ++i) {
        EXPECT_TRUE(queue.enqueue(TestData{.seq = i}));
    }

    EXPECT_FALSE(queue.empty());

    auto next = 0u;
    while (auto maybeValue = queue.dequeue()) {
        EXPECT_EQ(maybeValue->seq, next++);
    }

    EXPECT_TRUE(queue.empty());
}

TEST(StrandedPriorityQueueTests, MultipleThreadsUnlimitedQueue)
{
    async::CoroExecutionContext realCtx{6};
    async::AnyExecutionContext ctx{realCtx};
    StrandedPriorityQueue<TestData> queue{ctx.makeStrand()};

    EXPECT_TRUE(queue.empty());
    static constexpr auto kTOTAL_THREADS = 5u;
    static constexpr auto kTOTAL_ITEMS_PER_THREAD = 100u;

    std::atomic_size_t totalEnqueued = 0uz;
    std::vector<async::AnyOperation<void>> tasks;
    tasks.reserve(kTOTAL_THREADS);

    for (auto batchIdx = 0u; batchIdx < kTOTAL_THREADS; ++batchIdx) {
        // enqueue batches tasks running on multiple threads
        tasks.push_back(ctx.execute([&queue, batchIdx, &totalEnqueued] {
            for (auto i = 0u; i < kTOTAL_ITEMS_PER_THREAD; ++i) {
                if (queue.enqueue(TestData{.seq = (batchIdx * kTOTAL_ITEMS_PER_THREAD) + i}))
                    ++totalEnqueued;
            }
        }));
    }

    for (auto& task : tasks)
        task.wait();

    auto next = (kTOTAL_ITEMS_PER_THREAD * kTOTAL_THREADS) - 1;
    while (auto maybeValue = queue.dequeue()) {
        EXPECT_EQ(maybeValue->seq, next--);
    }

    EXPECT_TRUE(queue.empty());
    EXPECT_EQ(totalEnqueued, kTOTAL_ITEMS_PER_THREAD * kTOTAL_THREADS);
}

TEST(StrandedPriorityQueueTests, MultipleThreadsLimitedQueue)
{
    static constexpr auto kQUEUE_SIZE_LIMIT = 32uz;
    static constexpr auto kTOTAL_THREADS = 5u;
    static constexpr auto kTOTAL_ITEMS_PER_THREAD = 100u;

    async::CoroExecutionContext realCtx{8};
    async::AnyExecutionContext ctx{realCtx};
    StrandedPriorityQueue<TestData> queue{ctx.makeStrand(), kQUEUE_SIZE_LIMIT};

    EXPECT_TRUE(queue.empty());

    std::atomic_size_t totalEnqueued = 0uz;
    std::atomic_size_t totalSleepCycles = 0uz;
    std::vector<async::AnyOperation<void>> tasks;
    tasks.reserve(kTOTAL_THREADS);

    std::unordered_set<uint32_t> expectedSequences;

    for (auto batchIdx = 0u; batchIdx < kTOTAL_THREADS; ++batchIdx) {
        for (auto i = 0u; i < kTOTAL_ITEMS_PER_THREAD; ++i) {
            expectedSequences.insert((batchIdx * kTOTAL_ITEMS_PER_THREAD) + i);
        }

        // enqueue batches tasks running on multiple threads
        tasks.push_back(ctx.execute([&queue, batchIdx, &totalEnqueued, &totalSleepCycles] {
            for (auto i = 0u; i < kTOTAL_ITEMS_PER_THREAD; ++i) {
                auto data = TestData{.seq = (batchIdx * kTOTAL_ITEMS_PER_THREAD) + i};
                while (not queue.enqueue(data)) {
                    std::this_thread::sleep_for(std::chrono::nanoseconds{1});
                    ++totalSleepCycles;
                }
                ++totalEnqueued;
            }
        }));
    }

    EXPECT_FALSE(expectedSequences.empty());

    auto loader = ctx.execute([&queue, &expectedSequences] {
        while (not expectedSequences.empty()) {
            while (auto maybeValue = queue.dequeue()) {
                EXPECT_TRUE(expectedSequences.contains(maybeValue->seq));
                expectedSequences.erase(maybeValue->seq);
            }
        }
    });

    for (auto& task : tasks)
        task.wait();
    loader.wait();

    EXPECT_TRUE(queue.empty());
    EXPECT_TRUE(expectedSequences.empty());
    EXPECT_EQ(totalEnqueued, kTOTAL_ITEMS_PER_THREAD * kTOTAL_THREADS);
    EXPECT_GE(totalSleepCycles, 1uz);
}

TEST(StrandedPriorityQueueTests, ReturnsNulloptIfQueueEmpty)
{
    async::CoroExecutionContext realCtx;
    StrandedPriorityQueue<TestData> queue{realCtx.makeStrand()};

    EXPECT_TRUE(queue.empty());
    auto maybeValue = queue.dequeue();
    EXPECT_FALSE(maybeValue.has_value());
}