diff --git a/tree/treeplayer/test/data.h b/tree/treeplayer/test/data.h
index f6dafdd8a3f97..ec2d8947b14d5 100644
--- a/tree/treeplayer/test/data.h
+++ b/tree/treeplayer/test/data.h
@@ -2,14 +2,39 @@
 #define TTREEREADER_LEAF_TEST_DATA
 
 #include <vector>
-struct Data {
-   unsigned int fUSize;
-   int fSize;
-   double* fArray; //[fSize]
-   float* fUArray; //[fUSize]
-   std::vector<double> fVec;
-   Double32_t fDouble32;
-   Float16_t fFloat16;
+class Data {
+   unsigned int fUSize{};
+   int fSize{};
+   double *fArray{nullptr}; //[fSize]
+   float *fUArray{nullptr}; //[fUSize]
+   std::vector<double> fVec{};
+   Double32_t fDouble32{};
+   Float16_t fFloat16{};
+
+public:
+   Data() = default;
+   Data(const Data &) = delete;
+   Data &operator=(const Data &) = delete;
+   Data(Data &&) = delete;
+   Data &operator=(Data &&) = delete;
+   ~Data()
+   {
+      delete[] fArray;
+      fArray = nullptr;
+      delete[] fUArray;
+      fUArray = nullptr;
+   }
+   void Init()
+   {
+      fUSize = 2;
+      fSize = 4;
+      fArray = new double[4]{12., 13., 14., 15.};
+      fUArray = new float[2]{42., 43.};
+      fVec = {17., 18., 19., 20., 21., 22.};
+      fDouble32 = 17.;
+      fFloat16 = 44.;
+   }
+   std::vector<double> &GetVecMember() { return fVec; }
 };
 
 struct V {
diff --git a/tree/treeplayer/test/leafs.cxx b/tree/treeplayer/test/leafs.cxx
index 69ed3fc3d4447..a219b13999524 100644
--- a/tree/treeplayer/test/leafs.cxx
+++ b/tree/treeplayer/test/leafs.cxx
@@ -84,32 +84,26 @@ TEST(TTreeReaderLeafs, LeafListCaseA) {
    EXPECT_EQ(Bool, *trBool);
 }
 
-
-
-std::unique_ptr<TTree> CreateTree() {
+std::unique_ptr<TTree> CreateTree()
+{
    TInterpreter::EErrorCode error = TInterpreter::kNoError;
    gInterpreter->ProcessLine("#include \"data.h\"", &error);
    if (error != TInterpreter::kNoError)
       return {};
 
    Data data;
+   data.Init();
+   auto &vecDataMember = data.GetVecMember();
    auto tree = std::make_unique<TTree>("T", "test tree");
    tree->Branch("Data", &data);
-   data.fArray = new double[4]{12., 13., 14., 15.};
-   data.fSize = 4;
-   data.fUArray = new float[2]{42., 43.};
-   data.fUSize = 2;
-   data.fVec = { 17., 18., 19., 20., 21., 22.};
-   data.fDouble32 = 17.;
-   data.fFloat16 = 44.;
    tree->Fill();
 
-   data.fVec.clear();
-   data.fVec.resize(3210, 1001.f); // ROOT-8747
+   vecDataMember.clear();
+   vecDataMember.resize(3210, 1001.f); // ROOT-8747
    tree->Fill();
 
-   data.fVec.clear();
-   data.fVec.resize(2, 42.f); // ROOT-8747
+   vecDataMember.clear();
+   vecDataMember.resize(2, 42.f); // ROOT-8747
    tree->Fill();
 
    tree->ResetBranchAddresses();