Test warnings about signedness in comparisons in reco_particle_ref.cc

[wdconinc]

• Goal: I'm attempting to compile EDM4hep in LCG with a more recent version of podio than is present in LCG_101
• OS version: LCG_101/x86_64-ubuntu2004-gcc9-opt
• Compiler version: gcc9
• Package version: ffcdb0b
• Reproduced by (originally inside a GitHub action with run-lcg-views), as in Test failure due to missing symbol _ZN7edm4hep17MutableMCParticle11setMomentumENS_8Vector3fE on LCG_101 ubuntu #167 :

#    - name: Build in LCG view
#      uses: aidasoft/run-lcg-view@v1
#      with:
#        release-platform: ${{ matrix.LCG }}
#        run: |

docker run --rm -it -v /cvmfs:/cvmfs:shared ghcr.io/aidasoft/ubuntu2004:latest /bin/bash
source /cvmfs/sft.cern.ch/lcg/views/LCG_101/x86_64-ubuntu2004-gcc9-opt/setup.sh
git clone https://github.com/AIDAsoft/podio
git clone https://github.com/key4hep/edm4hep

          # build podio
          cmake -B podio-build -S podio \
            -DCMAKE_INSTALL_PREFIX=podio-install \
            -DUSE_EXTERNAL_CATCH2=OFF
          make -C podio-build -j6 install
          
          # build EDM4HEP
          export PODIO=$PWD/podio-install
          unset CMAKE_PREFIX_PATH
          cmake -B edm4hep-build -S edm4hep \
            -DCMAKE_INSTALL_PREFIX=edm4hep-install \
            -DUSE_EXTERNAL_CATCH2=OFF
          make -C edm4hep-build -j6 install

This returns (only) the following compilation warnings (in addition to the issue in #167):

/edm4hep/test/reco_particle_ref.cc: In function 'void writeRecoParticleRef(const TestState&)':
/edm4hep/test/reco_particle_ref.cc:31:25: warning: comparison of integer expressions of different signedness: 'size_t' {aka 'long unsigned int'} and 'const value_type' {aka 'const int'} [-Wsign-compare]
   31 |   ASSERT_CONDITION(left == right, msg.str())                              \
/edm4hep/test/reco_particle_ref.cc:22:10: note: in definition of macro 'ASSERT_CONDITION'
   22 |   if ( !(condition) ) {                                                      \
      |          ^~~~~~~~~
/edm4hep/test/reco_particle_ref.cc:133:5: note: in expansion of macro 'ASSERT_EQUAL'
  133 |     ASSERT_EQUAL(recoColl.size(), testState.nEntries[iEvent], "Created wrong number of entries");
      |     ^~~~~~~~~~~~
/edm4hep/test/reco_particle_ref.cc:31:25: warning: comparison of integer expressions of different signedness: 'size_t' {aka 'long unsigned int'} and 'const value_type' {aka 'const int'} [-Wsign-compare]
   31 |   ASSERT_CONDITION(left == right, msg.str())                              \
/edm4hep/test/reco_particle_ref.cc:22:10: note: in definition of macro 'ASSERT_CONDITION'
   22 |   if ( !(condition) ) {                                                      \
      |          ^~~~~~~~~
/edm4hep/test/reco_particle_ref.cc:134:5: note: in expansion of macro 'ASSERT_EQUAL'
  134 |     ASSERT_EQUAL(refColl.size(), testState.nRefs[iEvent], "Created wrong number of references");
      |     ^~~~~~~~~~~~
/edm4hep/test/reco_particle_ref.cc: In function 'void readRecoParticleRef(const TestState&)':
/edm4hep/test/reco_particle_ref.cc:31:25: warning: comparison of integer expressions of different signedness: 'size_t' {aka 'long unsigned int'} and 'const value_type' {aka 'const int'} [-Wsign-compare]
   31 |   ASSERT_CONDITION(left == right, msg.str())                              \
/edm4hep/test/reco_particle_ref.cc:22:10: note: in definition of macro 'ASSERT_CONDITION'
   22 |   if ( !(condition) ) {                                                      \
      |          ^~~~~~~~~
/edm4hep/test/reco_particle_ref.cc:159:5: note: in expansion of macro 'ASSERT_EQUAL'
  159 |     ASSERT_EQUAL(recoColl.size(), testState.nEntries[iEvent],
      |     ^~~~~~~~~~~~
/edm4hep/test/reco_particle_ref.cc:31:25: warning: comparison of integer expressions of different signedness: 'size_t' {aka 'long unsigned int'} and 'const value_type' {aka 'const int'} [-Wsign-compare]
   31 |   ASSERT_CONDITION(left == right, msg.str())                              \
/edm4hep/test/reco_particle_ref.cc:22:10: note: in definition of macro 'ASSERT_CONDITION'
   22 |   if ( !(condition) ) {                                                      \
      |          ^~~~~~~~~
/edm4hep/test/reco_particle_ref.cc:164:5: note: in expansion of macro 'ASSERT_EQUAL'
  164 |     ASSERT_EQUAL(refColl.size(), testState.nRefs[iEvent],
      |     ^~~~~~~~~~~~

[tmadlener]

Related: #123