Explore RCBase behaviour with tests

GeoModelCore/GeoModelKernel/CMakeLists.txt

@@ -48,7 +48,7 @@ install( FILES ${HEADERS}
    COMPONENT Development )
 
 
-   file(GLOB_RECURSE files "tests/*.cxx")
+file(GLOB_RECURSE files "tests/*.cxx")
 foreach(_exeFile ${files})
   get_filename_component(_theExec ${_exeFile} NAME_WE)
   get_filename_component(_theLoc ${_exeFile} DIRECTORY)
@@ -58,8 +58,11 @@ foreach(_exeFile ${files})
   endif()
 
   add_executable(${_theExec} ${_exeFile})
-  target_link_libraries( ${_theExec} GeoModelKernel)
+  target_link_libraries( ${_theExec} GeoModelKernel GTest::GTest GTest::Main)
   add_test(NAME ${_theExec}
            COMMAND ${_theExec})
 
 endforeach()
+include(GoogleTest)
+gtest_discover_tests(testRCBase)
+

GeoModelCore/GeoModelKernel/GeoModelKernel/RCBase.h

@@ -7,8 +7,8 @@
  *
  * @brief This is a base class for objects whose memory is managed
  *	through reference counting.  Reference-counted objects
- *	can only be created using
- *	operator new, the cannot be created on the stack.
+ *	should only be created using
+ *	operator new, they should not be created on the stack.
  *
  *	The methods ref() and unref() can be called to increase
  *	and decrease the reference count of an object.  When

GeoModelCore/GeoModelKernel/tests/testRCBase.cxx

+/*
+  Copyright (C) 2002-2025 CERN for the benefit of the ATLAS collaboration
+*/
+
+
+#include "GeoModelKernel/RCBase.h"
+#include <gtest/gtest.h>
+#include <limits>
+
+class Stub:public RCBase{
+  public:
+  Stub() = default;
+  virtual ~Stub() = default;
+};
+
+TEST(GeoModelKernel, RCBaseStub_CanBeConstructedOnStack) {
+  EXPECT_NO_THROW([[maybe_unused]] Stub stub);
+  //Stub stub1; (unused here if the following are commented out)
+  //none of the following compile (correctly so)
+  //Stub stub2(stub1);
+  //Stub stub3 = stub1;
+  //Stub stub4(std::move(stub1);
+  //Stub stub5 = std::move(stub3);
+}
+
+TEST(GeoModelKernel, RCBase_CanBeConstructedOnHeap) {
+  RCBase * p{};
+  EXPECT_NO_THROW(p = new RCBase);
+  EXPECT_NE(p, nullptr);
+  //deliberate leak here, RCBase d'tor is protected, so cannot delete
+}
+
+TEST(GeoModelKernel, RCBaseStub_CanBeConstructedOnHeap) {
+  Stub * p{};
+  EXPECT_NO_THROW(p = new Stub);
+  EXPECT_NE(p, nullptr);
+  //can delete the derived class directly
+  EXPECT_NO_THROW(delete p);
+}
+
+TEST(GeoModelKernel, RCBaseStub_ReferenceCountOk){
+  //do on heap, as is supposed to be
+  Stub * pStub = new Stub;
+  EXPECT_EQ(pStub->refCount(), 0);
+  EXPECT_NO_THROW(pStub->ref());
+  EXPECT_EQ(pStub->refCount(), 1);
+  EXPECT_NO_THROW(pStub->unref());
+  //now, where is the object? The pointer has not been set to zero.. so...
+  //the following line would execute (not crash) and return a nonsense value, 
+  //EXPECT_EQ(pStub->refCount(), 0); //returns 2043 on my machine
+  //segfault : delete pStub;
+  Stub * pStub2 = new Stub;
+  EXPECT_NO_THROW(pStub2->unref());
+  EXPECT_EQ(pStub2->refCount(), std::numeric_limits<unsigned int>::max());
+  //now it's cursed, so euthanise it
+  delete pStub2;
+}
\ No newline at end of file