tests: richer MockDDS (subscriptions, queues, seq) and link into Qt/GTest smoke-tests

Lts/DDS/DdsUnitTestsPlaceholder/mocks/MockDDS.cpp

@@ -4,24 +4,62 @@
 
 namespace MockDDS {
 
-static std::map<std::string, std::string> g_last_message;
+struct TopicState {
+  std::vector<std::string> queue;
+  std::map<SubscriptionId, Subscriber> subs;
+  SubscriptionId next_sub_id{1};
+  unsigned long seq{0};
+};
+
+static std::map<std::string, TopicState> g_topics;
 static std::mutex g_mtx;
 
 void publish(const std::string &topic, const std::string &msg) {
     std::lock_guard<std::mutex> lk(g_mtx);
-    g_last_message[topic] = msg;
+    auto &ts = g_topics[topic];
+    ts.seq++;
+    // annotate payload with simple seq metadata for basic QoS checks
+    std::string annotated = std::to_string(ts.seq) + ":" + msg;
+    ts.queue.push_back(annotated);
+    // notify subscribers synchronously
+    for (auto &p : ts.subs) {
+        auto &cb = p.second;
+        if (cb) cb(annotated);
+    }
+}
+
+MockDDS::SubscriptionId subscribe(const std::string &topic, Subscriber cb) {
+    std::lock_guard<std::mutex> lk(g_mtx);
+    auto &ts = g_topics[topic];
+    SubscriptionId id = ts.next_sub_id++;
+    ts.subs.emplace(id, std::move(cb));
+    return id;
+}
+
+void unsubscribe(const std::string &topic, SubscriptionId id) {
+    std::lock_guard<std::mutex> lk(g_mtx);
+    auto it = g_topics.find(topic);
+    if (it == g_topics.end()) return;
+    it->second.subs.erase(id);
 }
 
 std::string take_last(const std::string &topic) {
     std::lock_guard<std::mutex> lk(g_mtx);
-    auto it = g_last_message.find(topic);
-    if (it == g_last_message.end()) return std::string();
-    return it->second;
+    auto it = g_topics.find(topic);
+    if (it == g_topics.end() || it->second.queue.empty()) return std::string();
+    return it->second.queue.back();
+}
+
+std::vector<std::string> get_queue(const std::string &topic) {
+    std::lock_guard<std::mutex> lk(g_mtx);
+    auto it = g_topics.find(topic);
+    if (it == g_topics.end()) return {};
+    return it->second.queue;
 }
 
 void clear_all() {
     std::lock_guard<std::mutex> lk(g_mtx);
-    g_last_message.clear();
+    g_topics.clear();
 }
 
 } // namespace MockDDS

Lts/DDS/DdsUnitTestsPlaceholder/mocks/MockDDS.h

@@ -1,11 +1,26 @@
 #pragma once
 #include <string>
+#include <functional>
+#include <vector>
 
 namespace MockDDS {
 
-// Very small mock: single-writer, single-last-message per topic store.
+// Richer mock for migration smoke-tests:
+// - publish(topic, payload)
+// - 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)
+
+using Subscriber = std::function<void(const std::string &payload)>;
+using SubscriptionId = unsigned long;
+
 void publish(const std::string &topic, const std::string &msg);
+SubscriptionId subscribe(const std::string &topic, Subscriber cb);
+void unsubscribe(const std::string &topic, SubscriptionId id);
 std::string take_last(const std::string &topic);
+std::vector<std::string> get_queue(const std::string &topic);
 void clear_all();
 
 }