Add ini, test file

Author: ddobrigk

MC/config/common/ini/pythia8_inel_difftuned.ini

@@ -0,0 +1,2 @@
+[GeneratorPythia8]
+config=${O2DPG_MC_CONFIG_ROOT}/MC/config/common/pythia8/generator/pythia8_inel_difftuned.cfg

MC/config/common/ini/tests/pythia8_inel_difftuned.C

@@ -0,0 +1,24 @@
+int External() {
+  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");
+  if (!tree) {
+    std::cerr << "Cannot find tree o2sim in file " << path << "\n";
+    return 1;
+  }
+  std::vector<o2::MCTrack> *tracks{};
+  tree->SetBranchAddress("MCTrack", &tracks);
+
+  auto nEvents = tree->GetEntries();
+  if (nEvents == 0) {
+    std::cerr << "No event of interest\n";
+    return 1;
+  }
+  return 0;
+}