diff --git a/Lts/Common/CommonUnitTestsPlaceholder/CMakeLists.txt b/Lts/Common/CommonUnitTestsPlaceholder/CMakeLists.txt
new file mode 100644
index 000000000..2864c81b1
--- /dev/null
+++ b/Lts/Common/CommonUnitTestsPlaceholder/CMakeLists.txt
@@ -0,0 +1,32 @@
+cmake_minimum_required(VERSION 3.16)
+project(CommonUnitTestsPlaceholder)
+
+include(FetchContent)
+
+option(BUILD_SMOKE_TESTS "Build QtTest smoke tests" OFF)
+option(BUILD_GTEST_SMOKE "Build GTest smoke tests" OFF)
+
+add_subdirectory(mocks)
+
+if(BUILD_SMOKE_TESTS)
+  find_package(Qt6 REQUIRED COMPONENTS Test)
+  add_executable(coordTransTests_smoke coordTransTests_smoke.cpp)
+  target_link_libraries(coordTransTests_smoke PRIVATE Qt6::Test MockCoordTrans::MockCoordTrans)
+  add_test(NAME coordTransTests_smoke COMMAND coordTransTests_smoke)
+endif()
+
+if(BUILD_GTEST_SMOKE)
+  find_package(GTest QUIET)
+  if(NOT GTest_FOUND)
+    FetchContent_Declare(
+      googletest
+      GIT_REPOSITORY https://github.com/google/googletest.git
+      GIT_TAG release-1.12.1
+    )
+    set(gtest_force_shared_crt ON CACHE BOOL "" FORCE)
+    FetchContent_MakeAvailable(googletest)
+  endif()
+  add_executable(coordTransTests_gtest coordTransTests_gtest.cpp)
+  target_link_libraries(coordTransTests_gtest PRIVATE GTest::gtest_main MockCoordTrans::MockCoordTrans)
+  add_test(NAME coordTransTests_gtest COMMAND coordTransTests_gtest)
+endif()
diff --git a/Lts/Common/CommonUnitTestsPlaceholder/coordTransTests_gtest.cpp b/Lts/Common/CommonUnitTestsPlaceholder/coordTransTests_gtest.cpp
new file mode 100644
index 000000000..b0fc3f57e
--- /dev/null
+++ b/Lts/Common/CommonUnitTestsPlaceholder/coordTransTests_gtest.cpp
@@ -0,0 +1,12 @@
+#include "mocks/MockCoordTrans.h"
+#include <gtest/gtest.h>
+
+TEST(CoordTransGTest, ForwardInverseRoundtrip) {
+  auto p = MockCoordTrans::forward(1.2345, 2.3456);
+  EXPECT_NEAR(p.first, 1.2345 * 111000.0, 1e-6);
+  EXPECT_NEAR(p.second, 2.3456 * 111000.0, 1e-6);
+
+  auto inv = MockCoordTrans::inverse(p.first, p.second);
+  EXPECT_NEAR(inv.first, 1.2345, 1e-9);
+  EXPECT_NEAR(inv.second, 2.3456, 1e-9);
+}
diff --git a/Lts/Common/CommonUnitTestsPlaceholder/coordTransTests_smoke.cpp b/Lts/Common/CommonUnitTestsPlaceholder/coordTransTests_smoke.cpp
new file mode 100644
index 000000000..d5a177c35
--- /dev/null
+++ b/Lts/Common/CommonUnitTestsPlaceholder/coordTransTests_smoke.cpp
@@ -0,0 +1,15 @@
+#include <QtTest/QtTest>
+#include "mocks/MockCoordTrans.h"
+
+class CoordTransSmoke : public QObject {
+  Q_OBJECT
+private slots:
+  void testForward() {
+    auto p = MockCoordTrans::forward(10.0, 20.0);
+    QVERIFY(qFuzzyCompare(p.first, 10.0 * 111000.0));
+    QVERIFY(qFuzzyCompare(p.second, 20.0 * 111000.0));
+  }
+};
+
+QTEST_MAIN(CoordTransSmoke)
+#include "coordTransTests_smoke.moc"
diff --git a/Lts/Common/CommonUnitTestsPlaceholder/mocks/CMakeLists.txt b/Lts/Common/CommonUnitTestsPlaceholder/mocks/CMakeLists.txt
new file mode 100644
index 000000000..9e634c072
--- /dev/null
+++ b/Lts/Common/CommonUnitTestsPlaceholder/mocks/CMakeLists.txt
@@ -0,0 +1,5 @@
+add_library(MockCoordTrans STATIC MockCoordTrans.h)
+target_include_directories(MockCoordTrans PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})
+
+# Export header-only semantics by providing an interface target
+add_library(MockCoordTrans::MockCoordTrans ALIAS MockCoordTrans)
diff --git a/Lts/Common/CommonUnitTestsPlaceholder/mocks/MockCoordTrans.h b/Lts/Common/CommonUnitTestsPlaceholder/mocks/MockCoordTrans.h
new file mode 100644
index 000000000..5028ddc30
--- /dev/null
+++ b/Lts/Common/CommonUnitTestsPlaceholder/mocks/MockCoordTrans.h
@@ -0,0 +1,16 @@
+#pragma once
+#include <utility>
+
+// Minimal realistic mock for coordinate transforms used during migration.
+// Forward conversion returns approximate meters using lat/lon*111000.
+class MockCoordTrans {
+public:
+  // approximate forward: (lat, lon) -> (x_m, y_m)
+  static std::pair<double,double> forward(double lat_deg, double lon_deg) {
+    return {lat_deg * 111000.0, lon_deg * 111000.0};
+  }
+  // approximate inverse
+  static std::pair<double,double> inverse(double x_m, double y_m) {
+    return {x_m / 111000.0, y_m / 111000.0};
+  }
+};