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clio/tests/unit/util/ObservableValueAtomicTest.cpp
2025-12-09 10:36:53 +00:00

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//------------------------------------------------------------------------------
/*
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
purpose with or without fee is hereby granted, provided that the above
copyright notice and this permission notice appear in all copies.
THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
//==============================================================================
#include "util/ObservableValue.hpp"
#include <boost/signals2/connection.hpp>
#include <gmock/gmock.h>
#include <gtest/gtest.h>
#include <atomic>
#include <chrono>
#include <mutex>
#include <thread>
#include <vector>
using namespace testing;
using namespace util;
namespace {
} // namespace
class ObservableValueAtomicTest : public ::testing::Test {};
TEST_F(ObservableValueAtomicTest, BasicConstruction)
{
ObservableValue<std::atomic<int>> const obs{42};
EXPECT_EQ(obs.get(), 42);
EXPECT_EQ(static_cast<int>(obs), 42);
EXPECT_FALSE(obs.hasObservers());
}
TEST_F(ObservableValueAtomicTest, DefaultConstruction)
{
ObservableValue<std::atomic<int>> const obsInt;
EXPECT_EQ(obsInt.get(), 0);
ObservableValue<std::atomic<bool>> const obsBool;
EXPECT_FALSE(obsBool.get());
EXPECT_FALSE(obsInt.hasObservers());
EXPECT_FALSE(obsBool.hasObservers());
}
TEST_F(ObservableValueAtomicTest, BasicObservation)
{
ObservableValue<std::atomic<int>> obs{10};
testing::StrictMock<testing::MockFunction<void(int const&)>> mockObserver;
auto connection = obs.observe(mockObserver.AsStdFunction());
EXPECT_CALL(mockObserver, Call(20));
obs = 20;
EXPECT_EQ(obs.get(), 20);
}
TEST_F(ObservableValueAtomicTest, SetMethod)
{
ObservableValue<std::atomic<int>> obs{5};
testing::StrictMock<testing::MockFunction<void(int const&)>> mockObserver;
auto connection = obs.observe(mockObserver.AsStdFunction());
EXPECT_CALL(mockObserver, Call(15));
obs.set(15);
EXPECT_EQ(obs.get(), 15);
obs.set(15); // Same value should not notify
EXPECT_EQ(obs.get(), 15);
}
TEST_F(ObservableValueAtomicTest, AtomicBasicUsage)
{
ObservableValue<std::atomic<int>> obs{10};
testing::StrictMock<testing::MockFunction<void(int const&)>> mockObserver;
auto connection = obs.observe(mockObserver.AsStdFunction());
EXPECT_CALL(mockObserver, Call(25));
obs.set(25);
EXPECT_EQ(obs.get(), 25);
}
TEST_F(ObservableValueAtomicTest, AtomicMultipleChanges)
{
ObservableValue<std::atomic<int>> obs{50};
testing::StrictMock<testing::MockFunction<void(int const&)>> mockObserver;
auto connection = obs.observe(mockObserver.AsStdFunction());
EXPECT_CALL(mockObserver, Call(100)); // First change: 50→100
EXPECT_CALL(mockObserver, Call(50)); // Second change: 100→50
obs.set(100); // Should notify: 50→100
obs.set(50); // Should notify: 100→50
EXPECT_EQ(obs.get(), 50);
}
TEST_F(ObservableValueAtomicTest, AtomicNoChangeNoNotification)
{
ObservableValue<std::atomic<int>> obs{42};
testing::StrictMock<testing::MockFunction<void(int const&)>> mockObserver;
auto connection = obs.observe(mockObserver.AsStdFunction());
// No EXPECT_CALL since no notification should occur
obs.set(42); // Same value, should not notify
obs.set(42); // Same value again, should not notify
EXPECT_EQ(obs.get(), 42);
}
TEST_F(ObservableValueAtomicTest, AtomicSequentialChanges)
{
ObservableValue<std::atomic<int>> obs{1};
testing::StrictMock<testing::MockFunction<void(int const&)>> mockObserver;
auto connection = obs.observe(mockObserver.AsStdFunction());
EXPECT_CALL(mockObserver, Call(2));
obs.set(2);
EXPECT_CALL(mockObserver, Call(3));
obs.set(3);
EXPECT_EQ(obs.get(), 3);
}
TEST_F(ObservableValueAtomicTest, MultipleObservers)
{
ObservableValue<std::atomic<int>> obs{0};
testing::StrictMock<testing::MockFunction<void(int const&)>> mockObserver1;
testing::StrictMock<testing::MockFunction<void(int const&)>> mockObserver2;
auto conn1 = obs.observe(mockObserver1.AsStdFunction());
auto conn2 = obs.observe(mockObserver2.AsStdFunction());
EXPECT_CALL(mockObserver1, Call(42));
EXPECT_CALL(mockObserver2, Call(42));
obs = 42;
conn1.disconnect();
EXPECT_CALL(mockObserver2, Call(100));
obs = 100;
}
TEST_F(ObservableValueAtomicTest, ThreadSafetyBasic)
{
ObservableValue<std::atomic<int>> obs{0};
std::atomic<int> notificationCount{0};
std::vector<int> values;
std::mutex valuesMutex;
auto connection = obs.observe([&](int const& value) {
notificationCount.fetch_add(1);
std::lock_guard<std::mutex> const lock(valuesMutex);
values.push_back(value);
});
static constexpr auto kNUM_THREADS = 4;
static constexpr auto kINCREMENTS_PER_THREAD = 100;
std::vector<std::thread> threads;
threads.reserve(kNUM_THREADS);
for (int i = 0; i < kNUM_THREADS; ++i) {
threads.emplace_back([&obs]() {
for (int j = 0; j < kINCREMENTS_PER_THREAD; ++j) {
int const expected = obs.get();
int const newValue = expected + 1;
obs.set(newValue);
std::this_thread::sleep_for(std::chrono::microseconds(1));
}
});
}
for (auto& thread : threads)
thread.join();
// Final value may be less than kNumThreads * kIncrementsPerThread due to race conditions
EXPECT_GT(obs.get(), 0);
EXPECT_GT(notificationCount.load(), 0);
std::lock_guard<std::mutex> const lock(valuesMutex);
for (auto const& value : values) {
EXPECT_GT(value, 0);
}
}
TEST_F(ObservableValueAtomicTest, ThreadSafetyWithDirectAccess)
{
ObservableValue<std::atomic<int>> obs{0};
std::atomic<int> notificationCount{0};
auto connection = obs.observe([&](int const&) { notificationCount.fetch_add(1); });
static constexpr auto kNUM_THREADS = 4;
static constexpr auto kOPERATIONS_PER_THREAD = 50;
std::vector<std::thread> threads;
threads.reserve(kNUM_THREADS);
for (int i = 0; i < kNUM_THREADS; ++i) {
threads.emplace_back([&obs]() {
for (int j = 0; j < kOPERATIONS_PER_THREAD; ++j) {
int const current = obs.get();
obs.set(current + 1);
std::this_thread::sleep_for(std::chrono::microseconds(1));
}
});
}
for (auto& thread : threads)
thread.join();
EXPECT_GT(obs.get(), 0);
EXPECT_GT(notificationCount.load(), 0);
}
TEST_F(ObservableValueAtomicTest, AtomicBoolSpecialization)
{
ObservableValue<std::atomic<bool>> obs{false};
testing::StrictMock<testing::MockFunction<void(bool const&)>> mockObserver;
auto connection = obs.observe(mockObserver.AsStdFunction());
EXPECT_CALL(mockObserver, Call(true));
obs = true;
EXPECT_TRUE(obs.get());
obs = true; // Same value should not notify
EXPECT_CALL(mockObserver, Call(false));
obs.set(false);
EXPECT_FALSE(obs.get());
}
TEST_F(ObservableValueAtomicTest, CompareAndSwapBehavior)
{
ObservableValue<std::atomic<int>> obs{10};
testing::StrictMock<testing::MockFunction<void(int const&)>> mockObserver;
auto connection = obs.observe(mockObserver.AsStdFunction());
// Test that compare-and-swap works correctly in set()
obs.set(10); // Same value, should not notify
EXPECT_CALL(mockObserver, Call(20));
obs.set(20); // Different value, should notify
}
TEST_F(ObservableValueAtomicTest, RaceConditionNotificationIntegrity)
{
ObservableValue<std::atomic<int>> obs{0};
std::atomic<int> notificationCount{0};
std::vector<int> values;
std::mutex valuesMutex;
auto connection = obs.observe([&](int const& value) {
notificationCount.fetch_add(1);
std::lock_guard<std::mutex> const lock(valuesMutex);
values.push_back(value);
});
static constexpr auto kNUM_THREADS = 10;
static constexpr auto kOPERATIONS_PER_THREAD = 20;
std::vector<std::thread> threads;
threads.reserve(kNUM_THREADS);
for (int i = 0; i < kNUM_THREADS; ++i) {
threads.emplace_back([&obs]() {
for (int j = 0; j < kOPERATIONS_PER_THREAD; ++j) {
obs.set(j % 3);
std::this_thread::sleep_for(std::chrono::microseconds(1));
}
});
}
for (auto& thread : threads)
thread.join();
EXPECT_GT(notificationCount.load(), 0);
std::lock_guard<std::mutex> const lock(valuesMutex);
for (auto const& value : values) {
EXPECT_GE(value, 0);
EXPECT_LE(value, 2);
}
int const finalValue = obs.get();
EXPECT_GE(finalValue, 0);
EXPECT_LE(finalValue, 2);
}
TEST_F(ObservableValueAtomicTest, DeterministicNotificationTest)
{
ObservableValue<std::atomic<int>> obs{0};
std::atomic<int> notificationCount{0};
std::vector<int> values;
std::mutex valuesMutex;
auto connection = obs.observe([&](int const& value) {
notificationCount.fetch_add(1);
std::lock_guard<std::mutex> const lock(valuesMutex);
values.push_back(value);
});
static constexpr auto kNUM_THREADS = 5;
std::vector<std::thread> threads;
threads.reserve(kNUM_THREADS);
for (int i = 0; i < kNUM_THREADS; ++i) {
threads.emplace_back([&obs, i]() { obs.set(i + 1); });
}
for (auto& thread : threads)
thread.join();
// Each thread sets a unique value, so expect exactly kNumThreads notifications
EXPECT_EQ(notificationCount.load(), kNUM_THREADS);
std::lock_guard<std::mutex> const lock(valuesMutex);
EXPECT_EQ(values.size(), kNUM_THREADS);
for (auto const& value : values) {
EXPECT_GE(value, 1);
EXPECT_LE(value, kNUM_THREADS);
}
int const finalValue = obs.get();
EXPECT_GE(finalValue, 1);
EXPECT_LE(finalValue, kNUM_THREADS);
}
TEST_F(ObservableValueAtomicTest, NoNotificationForSameValue)
{
ObservableValue<std::atomic<int>> obs{42};
std::atomic<int> notificationCount{0};
auto connection = obs.observe([&](int const&) { notificationCount.fetch_add(1); });
static constexpr auto kNUM_THREADS = 10;
std::vector<std::thread> threads;
threads.reserve(kNUM_THREADS);
for (int i = 0; i < kNUM_THREADS; ++i) {
threads.emplace_back([&obs]() { obs.set(42); });
}
for (auto& thread : threads)
thread.join();
EXPECT_EQ(notificationCount.load(), 0); // No notifications since value never changed
EXPECT_EQ(obs.get(), 42);
}
TEST_F(ObservableValueAtomicTest, AtomicRaceConditionCorrectness)
{
ObservableValue<std::atomic<int>> obs{0};
std::atomic<int> notificationCount{0};
std::vector<int> values;
std::mutex valuesMutex;
auto connection = obs.observe([&](int const& value) {
notificationCount.fetch_add(1);
std::lock_guard<std::mutex> const lock(valuesMutex);
values.push_back(value);
});
static constexpr auto kNUM_THREADS = 3;
std::vector<std::thread> threads;
threads.reserve(kNUM_THREADS);
// Test that direct access properly notifies for all value changes
// Each thread will make unique changes to avoid race condition conflicts
for (int i = 0; i < kNUM_THREADS; ++i) {
threads.emplace_back([&obs, i]() {
int const baseValue = (i + 1) * 10; // 10, 20, 30
obs.set(baseValue); // Store unique values
obs.set(baseValue + 1); // Then increment
});
}
for (auto& thread : threads)
thread.join();
// We should get some notifications (exact count depends on race conditions)
// but at least one per thread since they use unique base values
EXPECT_GE(notificationCount.load(), kNUM_THREADS);
std::lock_guard<std::mutex> const lock(valuesMutex);
EXPECT_GE(values.size(), kNUM_THREADS);
for (auto const& value : values)
EXPECT_GT(value, 0);
}
TEST_F(ObservableValueAtomicTest, ForceNotify)
{
ObservableValue<std::atomic<int>> obs{42};
testing::StrictMock<testing::MockFunction<void(int const&)>> mockObserver;
obs.forceNotify();
auto connection = obs.observe(mockObserver.AsStdFunction());
EXPECT_CALL(mockObserver, Call(42));
obs.forceNotify();
EXPECT_CALL(mockObserver, Call(42));
obs.forceNotify();
EXPECT_CALL(mockObserver, Call(100));
obs.set(100);
EXPECT_CALL(mockObserver, Call(100));
obs.forceNotify();
EXPECT_CALL(mockObserver, Call(100)).Times(3);
obs.forceNotify();
obs.forceNotify();
obs.forceNotify();
}