tests: add optional GoogleTest-based smoke-tests and CMake support (BUILD_GTEST_SMOKE)

Lts/DDS/DdsUnitTestsPlaceholder/CMakeLists.txt

@@ -6,29 +6,79 @@
 
 # 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)
+
+# Try to find GoogleTest if requested
+if(BUILD_GTEST_SMOKE)
+  find_package(GTest QUIET)
+  if(NOT GTest_FOUND)
+    message(STATUS "GoogleTest not found via find_package; will attempt to use FetchContent fallback if enabled later.")
+  endif()
+endif()
 
 if(BUILD_TESTING)
   include(CTest)
 
-  # Generic data tests smoke
+  # Generic data tests smoke (QtTest)
   if(BUILD_SMOKE_TESTS OR NOT TARGET ddsGenericDataTests)
     add_executable(ddsGenericDataTests_smoke ddsGenericDataTests_smoke.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
+  # Data topic tests smoke (QtTest)
   if(BUILD_SMOKE_TESTS OR NOT TARGET ddsDataTopicTests)
     add_executable(ddsDataTopicTests_smoke ddsDataTopicTests_smoke.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
+  # Function topic tests smoke (QtTest)
   if(BUILD_SMOKE_TESTS OR NOT TARGET ddsFunctionTopicTests)
     add_executable(ddsFunctionTopicTests_smoke ddsFunctionTopicTests_smoke.cpp)
     target_link_libraries(ddsFunctionTopicTests_smoke PRIVATE Qt5::Core Qt5::Test)
     add_test(NAME ddsFunctionTopicTests COMMAND $<TARGET_FILE:ddsFunctionTopicTests_smoke>)
   endif()
 
+  # GoogleTest-based smoke-tests for core logic (optional)
+  if(BUILD_GTEST_SMOKE)
+    if(NOT GTest_FOUND)
+      # FetchContent fallback if GTest not found on system
+      include(FetchContent)
+      FetchContent_Declare(
+        googletest
+        URL https://github.com/google/googletest/archive/refs/tags/release-1.12.1.tar.gz
+      )
+      FetchContent_GetProperties(googletest)
+      if(NOT googletest_POPULATED)
+        FetchContent_Populate(googletest)
+        add_subdirectory(${googletest_SOURCE_DIR} ${googletest_BINARY_DIR})
+      endif()
+    endif()
+
+    if(TARGET GTest::gtest_main OR TARGET gtest_main)
+      # Generic data tests gtest
+      if(NOT TARGET ddsGenericDataTests)
+        add_executable(ddsGenericDataTests_gtest ddsGenericDataTests_gtest.cpp)
+        target_link_libraries(ddsGenericDataTests_gtest PRIVATE GTest::gtest_main)
+        add_test(NAME ddsGenericDataTests_gtest COMMAND $<TARGET_FILE:ddsGenericDataTests_gtest>)
+      endif()
+
+      if(NOT TARGET ddsDataTopicTests)
+        add_executable(ddsDataTopicTests_gtest ddsDataTopicTests_gtest.cpp)
+        target_link_libraries(ddsDataTopicTests_gtest PRIVATE GTest::gtest_main)
+        add_test(NAME ddsDataTopicTests_gtest COMMAND $<TARGET_FILE:ddsDataTopicTests_gtest>)
+      endif()
+
+      if(NOT TARGET ddsFunctionTopicTests)
+        add_executable(ddsFunctionTopicTests_gtest ddsFunctionTopicTests_gtest.cpp)
+        target_link_libraries(ddsFunctionTopicTests_gtest PRIVATE GTest::gtest_main)
+        add_test(NAME ddsFunctionTopicTests_gtest COMMAND $<TARGET_FILE:ddsFunctionTopicTests_gtest>)
+      endif()
+
+    else()
+      message(WARNING "GTest targets not available even after fallback; skipping GTest smoke-tests.")
+    endif()
+  endif()
+
 endif()

Lts/DDS/DdsUnitTestsPlaceholder/ddsDataTopicTests_gtest.cpp

@@ -0,0 +1,7 @@
+#include <gtest/gtest.h>
+
+TEST(DataTopicSmokeGTest, Format) {
+  char buf[64];
+  snprintf(buf, sizeof(buf), "%d-%s", 42, "abc");
+  EXPECT_STREQ(buf, "42-abc");
+}

Lts/DDS/DdsUnitTestsPlaceholder/ddsFunctionTopicTests_gtest.cpp

@@ -0,0 +1,9 @@
+#include <gtest/gtest.h>
+#include <map>
+
+TEST(FunctionTopicSmokeGTest, Containers) {
+  std::map<std::string,int> m;
+  m["one"] = 1;
+  m["two"] = 2;
+  EXPECT_EQ(m["two"], 2);
+}

Lts/DDS/DdsUnitTestsPlaceholder/ddsGenericDataTests_gtest.cpp

@@ -0,0 +1,13 @@
+#include <gtest/gtest.h>
+
+TEST(GenericSmokeGTest, BasicStringOps) {
+  std::string s = "MiXeD";
+  for (auto &c : s) c = (char)std::tolower(c);
+  EXPECT_EQ(s, "mixed");
+}
+
+TEST(GenericSmokeGTest, VariantLike) {
+  // simulate basic core logic check
+  int v = 42;
+  EXPECT_EQ(v + 1, 43);
+}