Adds initial intermediate qt6 porting state

qt6-after/qt6-migrated-legatus/Lts/DDS/DdsUnitTestsPlaceholder/ddsDataTopicTests_gtest.cpp

@@ -0,0 +1,24 @@
+#include <gtest/gtest.h>
+#include "mocks/MockDDS.h"
+
+TEST(DataTopicSmokeGTest, Format) {
+  char buf[64];
+  snprintf(buf, sizeof(buf), "%d-%s", 42, "abc");
+  EXPECT_STREQ(buf, "42-abc");
+}
+
+TEST(DataTopicSmokeGTest, MockDDSTopicFlow) {
+  MockDDS::clear_all();
+  MockDDS::publish("data/topic", "hello");
+  auto r1 = MockDDS::take_last("data/topic");
+  auto p1 = r1.substr(r1.find(':') + 1);
+  EXPECT_EQ(p1, "hello");
+  MockDDS::publish("data/topic", "world");
+  auto r2 = MockDDS::take_last("data/topic");
+  auto p2 = r2.substr(r2.find(':') + 1);
+  EXPECT_EQ(p2, "world");
+  // check sequence increment
+  auto s1 = std::stoul(r1.substr(0, r1.find(':')));
+  auto s2 = std::stoul(r2.substr(0, r2.find(':')));
+  EXPECT_LT(s1, s2);
+}