Add test for OO cocktail

Author: hscheid

MC/config/PWGEM/ini/tests/GeneratorEMCocktail_Run3_OO.C

@@ -0,0 +1,64 @@
+int External()
+{
+    	
+    int checkPdgDecay = -11;
+    std::string path{"o2sim_Kine.root"};
+    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");
+    std::vector<o2::MCTrack>* tracks{};
+    tree->SetBranchAddress("MCTrack", &tracks);
+
+    int nMesons{};
+    int nMesonsDiElectronDecay{};
+    auto nEvents = tree->GetEntries();
+
+    for (int i = 0; i < nEvents; i++) {
+        tree->GetEntry(i);
+        for (auto& track : *tracks) {
+            auto pdg = track.GetPdgCode();
+            auto y = track.GetRapidity();
+            if ((pdg == 111) || (pdg == 221) || (pdg == 331) || (pdg == 223) || (pdg == 113) || (pdg == 333)) {
+	       if ((y>-1.2) && (y<1.2)) { 
+                  nMesons++;
+                  Int_t counterel = 0;
+                  Int_t counterpos = 0;
+                  int k1 = track.getFirstDaughterTrackId();
+                  int k2 = track.getLastDaughterTrackId();
+                  // k1 < k2 and no -1 for k2
+                  for (int d=k1; d <= k2; d++) {
+                      if (d>0) {
+                         auto decay = (*tracks)[d];
+                         int pdgdecay = decay.GetPdgCode();
+                         if (pdgdecay == 11) {
+                            counterel++;
+                         }
+                         if (pdgdecay == -11) {
+                            counterpos++;
+                         }
+                      }
+                  }
+                  if ((counterel>0) && (counterpos>0)) nMesonsDiElectronDecay++;
+               }
+           }
+        }
+    }	
+    
+    std::cout << "#events: " << nEvents << "\n"
+              << "#mesons: " << nMesons << "\n"
+              << "#mesons which decay semi-electronicly: " << nMesonsDiElectronDecay << "\n";
+    if (nMesonsDiElectronDecay < nEvents) {
+        std::cerr << "One should have at least one meson that decays into dielectrons per event.\n";
+        return 1;
+    }
+    if (nMesons < nEvents) {
+        std::cerr << "One meson per event should be produced.\n";
+        return 1;
+    }
+
+    return 0;
+}