roro9stack/test/test_event_bus/test_event_bus.cpp

#include <unity.h>

#include <string>
#include <vector>

#include "event_bus.h"

using namespace roro;

void setUp() {}
void tearDown() {}

void test_published_events_are_delivered_on_dispatch_not_before() {
    EventBus bus(8);
    int calls = 0;
    bus.subscribe(EventType::BatteryChanged, [&](const Event&) { calls++; });

    bus.publish(Event{EventType::BatteryChanged});
    TEST_ASSERT_EQUAL(0, calls);

    TEST_ASSERT_EQUAL(1, bus.dispatch());
    TEST_ASSERT_EQUAL(1, calls);
}

void test_only_subscribers_of_the_event_type_are_called() {
    EventBus bus(8);
    int battery = 0, notification = 0;
    bus.subscribe(EventType::BatteryChanged, [&](const Event&) { battery++; });
    bus.subscribe(EventType::Notification, [&](const Event&) { notification++; });

    bus.publish(Event{EventType::Notification});
    bus.dispatch();

    TEST_ASSERT_EQUAL(0, battery);
    TEST_ASSERT_EQUAL(1, notification);
}

void test_every_subscriber_of_a_type_is_called_in_subscription_order() {
    EventBus bus(8);
    std::vector<int> order;
    bus.subscribe(EventType::Notification, [&](const Event&) { order.push_back(1); });
    bus.subscribe(EventType::Notification, [&](const Event&) { order.push_back(2); });

    bus.publish(Event{EventType::Notification});
    bus.dispatch();

    TEST_ASSERT_EQUAL(2, order.size());
    TEST_ASSERT_EQUAL(1, order[0]);
    TEST_ASSERT_EQUAL(2, order[1]);
}

void test_events_keep_publish_order_and_payload() {
    EventBus bus(8);
    std::vector<int32_t> values;
    bus.subscribe(EventType::BatteryChanged, [&](const Event& e) { values.push_back(e.a); });

    bus.publish(Event::withValues(EventType::BatteryChanged, 80));
    bus.publish(Event::withValues(EventType::BatteryChanged, 79));
    bus.dispatch();

    TEST_ASSERT_EQUAL(2, values.size());
    TEST_ASSERT_EQUAL(80, values[0]);
    TEST_ASSERT_EQUAL(79, values[1]);
}

void test_text_payload_is_copied_and_truncated_safely() {
    EventBus bus(8);
    std::string received;
    bus.subscribe(EventType::Notification, [&](const Event& e) { received = e.text; });

    std::string longText(200, 'x');
    bus.publish(Event::withText(EventType::Notification, longText.c_str()));
    bus.dispatch();

    TEST_ASSERT_EQUAL(Event::kTextCapacity - 1, received.size());
}

void test_full_queue_drops_newest_and_counts_drops() {
    EventBus bus(2);
    std::vector<int32_t> values;
    bus.subscribe(EventType::BatteryChanged, [&](const Event& e) { values.push_back(e.a); });

    TEST_ASSERT_TRUE(bus.publish(Event::withValues(EventType::BatteryChanged, 1)));
    TEST_ASSERT_TRUE(bus.publish(Event::withValues(EventType::BatteryChanged, 2)));
    TEST_ASSERT_FALSE(bus.publish(Event::withValues(EventType::BatteryChanged, 3)));
    TEST_ASSERT_EQUAL(1, bus.dropped());

    bus.dispatch();
    TEST_ASSERT_EQUAL(2, values.size());
    TEST_ASSERT_EQUAL(2, values[1]);
}

void test_events_published_during_dispatch_wait_for_next_dispatch() {
    EventBus bus(8);
    int notifications = 0;
    bus.subscribe(EventType::BatteryChanged,
                  [&](const Event&) { bus.publish(Event{EventType::Notification}); });
    bus.subscribe(EventType::Notification, [&](const Event&) { notifications++; });

    bus.publish(Event{EventType::BatteryChanged});
    TEST_ASSERT_EQUAL(1, bus.dispatch());
    TEST_ASSERT_EQUAL(0, notifications);

    TEST_ASSERT_EQUAL(1, bus.dispatch());
    TEST_ASSERT_EQUAL(1, notifications);
}

int main() {
    UNITY_BEGIN();
    RUN_TEST(test_published_events_are_delivered_on_dispatch_not_before);
    RUN_TEST(test_only_subscribers_of_the_event_type_are_called);
    RUN_TEST(test_every_subscriber_of_a_type_is_called_in_subscription_order);
    RUN_TEST(test_events_keep_publish_order_and_payload);
    RUN_TEST(test_text_payload_is_copied_and_truncated_safely);
    RUN_TEST(test_full_queue_drops_newest_and_counts_drops);
    RUN_TEST(test_events_published_during_dispatch_wait_for_next_dispatch);
    return UNITY_END();
}