tests(dds): enable GTest smoke-tests and add async-capable realistic MockDDS with GTest async subscription test

Lts/DDS/DdsUnitTestsPlaceholder/CMakeLists.txt

@@ -6,7 +6,8 @@
 
 # Option to force-building smoke-tests even when real test targets exist.
 option(BUILD_SMOKE_TESTS "Build smoke-tests even if real test executables are present" OFF)
-option(BUILD_GTEST_SMOKE "Build GoogleTest-based smoke-tests for core logic" OFF)
+# Enable GTest smoke-tests during migration to exercise realistic DDS mocks
+option(BUILD_GTEST_SMOKE "Build GoogleTest-based smoke-tests for core logic" ON)
 
 # Try to find GoogleTest if requested
 if(BUILD_GTEST_SMOKE)
@@ -21,21 +22,21 @@ if(BUILD_TESTING)
 
   # Generic data tests smoke (QtTest)
   if(BUILD_SMOKE_TESTS OR NOT TARGET ddsGenericDataTests)
-    add_executable(ddsGenericDataTests_smoke ddsGenericDataTests_smoke.cpp)
+    add_executable(ddsGenericDataTests_smoke ddsGenericDataTests_smoke.cpp mocks/MockDDS.cpp)
     target_link_libraries(ddsGenericDataTests_smoke PRIVATE Qt5::Core Qt5::Test)
     add_test(NAME ddsGenericDataTests COMMAND $<TARGET_FILE:ddsGenericDataTests_smoke>)
   endif()
 
   # Data topic tests smoke (QtTest)
   if(BUILD_SMOKE_TESTS OR NOT TARGET ddsDataTopicTests)
-    add_executable(ddsDataTopicTests_smoke ddsDataTopicTests_smoke.cpp)
+    add_executable(ddsDataTopicTests_smoke ddsDataTopicTests_smoke.cpp mocks/MockDDS.cpp)
     target_link_libraries(ddsDataTopicTests_smoke PRIVATE Qt5::Core Qt5::Test)
     add_test(NAME ddsDataTopicTests COMMAND $<TARGET_FILE:ddsDataTopicTests_smoke>)
   endif()
 
   # Function topic tests smoke (QtTest)
   if(BUILD_SMOKE_TESTS OR NOT TARGET ddsFunctionTopicTests)
-    add_executable(ddsFunctionTopicTests_smoke ddsFunctionTopicTests_smoke.cpp)
+    add_executable(ddsFunctionTopicTests_smoke ddsFunctionTopicTests_smoke.cpp mocks/MockDDS.cpp)
     target_link_libraries(ddsFunctionTopicTests_smoke PRIVATE Qt5::Core Qt5::Test)
     add_test(NAME ddsFunctionTopicTests COMMAND $<TARGET_FILE:ddsFunctionTopicTests_smoke>)
   endif()

Lts/DDS/DdsUnitTestsPlaceholder/ddsGenericDataTests_gtest.cpp

@@ -1,5 +1,7 @@
 #include <gtest/gtest.h>
 #include "mocks/MockDDS.h"
+#include <mutex>
+#include <condition_variable>
 
 TEST(GenericSmokeGTest, BasicStringOps) {
   std::string s = "MiXeD";
@@ -19,3 +21,35 @@ TEST(GenericSmokeGTest, MockDDSPublishReceive) {
   EXPECT_EQ(payload, "payload42");
   EXPECT_EQ(seq, 1UL);
 }
+
+TEST(GenericSmokeGTest, MockDDSAsyncDelivery) {
+  MockDDS::clear_all();
+  std::mutex mtx;
+  std::condition_variable cv;
+  bool received = false;
+  std::string last;
+
+  auto cb = [&](const std::string &payload){
+    std::lock_guard<std::mutex> lk(mtx);
+    last = payload;
+    received = true;
+    cv.notify_one();
+  };
+
+  auto sub = MockDDS::subscribe("topic-async", cb);
+  // publish asynchronously with small delay; callback should be invoked
+  MockDDS::publish_async("topic-async", "async-payload", 20);
+
+  std::unique_lock<std::mutex> lk(mtx);
+  if (!cv.wait_for(lk, std::chrono::seconds(2), [&]{ return received; })) {
+    // timeout
+    MockDDS::unsubscribe("topic-async", sub);
+    FAIL() << "Did not receive async callback in time";
+  }
+  MockDDS::unsubscribe("topic-async", sub);
+  // parse annotation
+  auto pos = last.find(':');
+  ASSERT_NE(pos, std::string::npos);
+  auto payload = last.substr(pos + 1);
+  EXPECT_EQ(payload, "async-payload");
+}

Lts/DDS/DdsUnitTestsPlaceholder/mocks/MockDDS.cpp

@@ -1,6 +1,8 @@
 #include "MockDDS.h"
 #include <map>
 #include <mutex>
+#include <thread>
+#include <condition_variable>
 
 namespace MockDDS {
 
@@ -14,6 +16,51 @@ struct TopicState {
 static std::map<std::string, TopicState> g_topics;
 static std::mutex g_mtx;
 
+// Background dispatcher for async publishes
+static std::vector<std::tuple<std::string, std::string, unsigned>> g_async_queue;
+static std::mutex g_async_mtx;
+static std::condition_variable g_async_cv;
+static bool g_async_running = false;
+static std::thread g_async_thread;
+
+static void async_worker() {
+    std::unique_lock<std::mutex> lk(g_async_mtx);
+    while (g_async_running) {
+        if (g_async_queue.empty()) {
+            g_async_cv.wait(lk, [] { return !g_async_queue.empty() || !g_async_running; });
+            if (!g_async_running) break;
+        }
+        auto task = g_async_queue.front();
+        g_async_queue.erase(g_async_queue.begin());
+        lk.unlock();
+        auto &topic = std::get<0>(task);
+        auto &msg = std::get<1>(task);
+        unsigned delay_ms = std::get<2>(task);
+        if (delay_ms) std::this_thread::sleep_for(std::chrono::milliseconds(delay_ms));
+        // perform synchronous publish semantics for delivered message
+        {
+            std::lock_guard<std::mutex> lk2(g_mtx);
+            auto &ts = g_topics[topic];
+            ts.seq++;
+            std::string annotated = std::to_string(ts.seq) + ":" + msg;
+            ts.queue.push_back(annotated);
+            for (auto &p : ts.subs) {
+                auto &cb = p.second;
+                if (cb) cb(annotated);
+            }
+        }
+        lk.lock();
+    }
+}
+
+static void ensure_async_thread() {
+    std::lock_guard<std::mutex> lk(g_async_mtx);
+    if (!g_async_running) {
+        g_async_running = true;
+        g_async_thread = std::thread(async_worker);
+    }
+}
+
 void publish(const std::string &topic, const std::string &msg) {
     std::lock_guard<std::mutex> lk(g_mtx);
     auto &ts = g_topics[topic];
@@ -28,6 +75,15 @@ void publish(const std::string &topic, const std::string &msg) {
     }
 }
 
+void publish_async(const std::string &topic, const std::string &msg, unsigned delay_ms) {
+    ensure_async_thread();
+    {
+        std::lock_guard<std::mutex> lk(g_async_mtx);
+        g_async_queue.emplace_back(topic, msg, delay_ms);
+    }
+    g_async_cv.notify_one();
+}
+
 MockDDS::SubscriptionId subscribe(const std::string &topic, Subscriber cb) {
     std::lock_guard<std::mutex> lk(g_mtx);
     auto &ts = g_topics[topic];
@@ -58,8 +114,21 @@ std::vector<std::string> get_queue(const std::string &topic) {
 }
 
 void clear_all() {
-    std::lock_guard<std::mutex> lk(g_mtx);
-    g_topics.clear();
+    {
+        std::lock_guard<std::mutex> lk(g_mtx);
+        g_topics.clear();
+    }
+    // shutdown async worker gracefully
+    {
+        std::lock_guard<std::mutex> lk(g_async_mtx);
+        g_async_running = false;
+    }
+    g_async_cv.notify_all();
+    if (g_async_thread.joinable()) g_async_thread.join();
+    {
+        std::lock_guard<std::mutex> lk(g_async_mtx);
+        g_async_queue.clear();
+    }
 }
 
 } // namespace MockDDS

Lts/DDS/DdsUnitTestsPlaceholder/mocks/MockDDS.h

@@ -2,21 +2,24 @@
 #include <string>
 #include <functional>
 #include <vector>
+#include <chrono>
 
 namespace MockDDS {
 
 // Richer mock for migration smoke-tests:
-// - publish(topic, payload)
+// - publish(topic, payload)                        : synchronous publish
+// - publish_async(topic, payload, delay_ms)        : asynchronous publish (background dispatcher)
 // - subscribe(topic, callback) -> subscription id
 // - unsubscribe(topic, subscription id)
 // - take_last(topic), get_queue(topic)
 // - clear_all()
-// - sequence numbers per topic (as simple integer appended to payload meta)
+// - sequence numbers per topic (integer appended to payload meta)
 
 using Subscriber = std::function<void(const std::string &payload)>;
 using SubscriptionId = unsigned long;
 
 void publish(const std::string &topic, const std::string &msg);
+void publish_async(const std::string &topic, const std::string &msg, unsigned delay_ms = 0);
 SubscriptionId subscribe(const std::string &topic, Subscriber cb);
 void unsubscribe(const std::string &topic, SubscriptionId id);
 std::string take_last(const std::string &topic);