Add Pythia8 Forced Dalitz test config for pp 13.6 TeV

Author: Laura Gansbartl

MC/config/PWGEM/ini/tests/pythia8_pp_13600_ForcedDalitz.C

@@ -0,0 +1,57 @@
+int External() {
+    std::string path{"o2sim_Kine.root"};
+    // Check that file exists, can be opened and has the correct tree
+    TFile file(path.c_str(), "READ");
+    if (file.IsZombie())
+    {
+      std::cerr << "Cannot open ROOT file " << path << "\n";
+      return 1;
+    }
+    auto tree = (TTree *)file.Get("o2sim");
+    if (!tree)
+    {
+      std::cerr << "Cannot find tree o2sim in file " << path << "\n";
+      return 1;
+    }
+    std::vector<o2::MCTrack> *tracks{};
+    tree->SetBranchAddress("MCTrack", &tracks);
+  
+    // Check if all events are filled
+    auto nEvents = tree->GetEntries();
+    for (Long64_t i = 0; i < nEvents; ++i)
+    {
+      tree->GetEntry(i);
+      if (tracks->empty())
+      {
+        std::cerr << "Empty entry found at event " << i << "\n";
+        return 1;
+      }
+    }
+    // // check if each event has at least two oxygen ions
+    // for (int i = 0; i < nEvents; i++)
+    // {
+    //   auto check = tree->GetEntry(i);
+    //   int count = 0;
+    //   for (int idxMCTrack = 0; idxMCTrack < tracks->size(); ++idxMCTrack)
+    //   {
+    //     auto track = tracks->at(idxMCTrack);
+    //     if (track.GetPdgCode() == 1000080160)
+    //     {
+    //       count++;
+    //     }
+    //   }
+    //   if (count < 2)
+    //   {
+    //     std::cerr << "Event " << i << " has less than 2 oxygen ions\n";
+    //     return 1;
+    //   }
+    // }
+  
+    return 0;
+  }
+  
+  int pythia8()
+  {
+      return External();
+  }
+