ENH: Modernize Qt integration in LayerDM tests

- Replace manual QT5_GENERATE_MOCS with AUTOMOC
- Use find_package with Qt version detection (Qt5/Qt6)
- Simplify target linking with loop over Qt components
- Update moc include to use .moc extension convention
- Remove explicit Qt component dependencies in favor of dynamic linking

This change makes the test configuration more maintainable and
prepares the module for Qt6 compatibility.

Author: RafaelPalomar

LayerDM/Testing/Cxx/CMakeLists.txt

@@ -1,5 +1,11 @@
 set(KIT ${MODULE_NAME})
-find_package(Qt5 REQUIRED COMPONENTS Core Widgets Test)
+
+list(APPEND QT_REQUIRED_COMPONENTS Core Test)
+if(Slicer_REQUIRED_QT_VERSION VERSION_GREATER_EQUAL "6")
+  find_package(Qt6 COMPONENTS ${QT_REQUIRED_COMPONENTS} QUIET)
+else()
+  find_package(Qt5 COMPONENTS ${QT_REQUIRED_COMPONENTS} QUIET)
+endif()
 
 set(TEST_SOURCES
   NodeReferenceObserverTest.cxx
@@ -11,16 +17,24 @@ create_test_sourcelist(Tests ${KIT}CppTests.cxx
   EXTRA_INCLUDE ${EXTRA_INCLUDE}
 )
 
-QT5_GENERATE_MOCS(${TEST_SOURCES} USE_MOC_EXTENSION)
 include_directories(${CMAKE_CURRENT_BINARY_DIR})
 ctk_add_executable_utf8(${KIT}CxxTests ${Tests} ${Tests_MOC_CXX} ${Tests_UtilityFiles})
 
+set_target_properties(${KIT}CxxTests PROPERTIES
+  AUTOMOC ON
+)
+
+foreach(lib IN LISTS QT_REQUIRED_COMPONENTS)
+  if(Slicer_REQUIRED_QT_VERSION VERSION_GREATER_EQUAL "6")
+    list(APPEND MODULE_TARGET_LIBRARIES Qt6::${lib})
+  else()
+    list(APPEND MODULE_TARGET_LIBRARIES Qt5::${lib})
+  endif()
+endforeach()
+
 target_link_libraries(
   ${KIT}CxxTests
   ${MODULE_TARGET_LIBRARIES}
-  Qt5::Core
-  Qt5::Test
-  Qt5::Widgets
 )
 
 include(SlicerMacroSimpleTest)

LayerDM/Testing/Cxx/NodeReferenceObserverTest.cxx

@@ -249,4 +249,5 @@ private slots:
 };
 
 CTK_TEST_MAIN(NodeReferenceObserverTest)
-#include "moc_NodeReferenceObserverTest.cxx"
+
+#include "NodeReferenceObserverTest.moc"