diff --git a/test/blobstore/implementations/onblocks/datatreestore/DataTreeTest_Performance.cpp b/test/blobstore/implementations/onblocks/datatreestore/DataTreeTest_Performance.cpp
index 23150d6d..5cab42a8 100644
--- a/test/blobstore/implementations/onblocks/datatreestore/DataTreeTest_Performance.cpp
+++ b/test/blobstore/implementations/onblocks/datatreestore/DataTreeTest_Performance.cpp
@@ -14,31 +14,183 @@ using cpputils::make_unique_ref;
 
 class DataTreeTest_Performance: public DataTreeTest {
 public:
+    void Traverse(DataTree *tree, uint64_t beginIndex, uint64_t endIndex) {
+        tree->traverseLeaves(beginIndex, endIndex, [] (uint32_t /*index*/, DataLeafNode* /*leaf*/) {}, [this] (uint32_t /*index*/) -> Data {return Data(maxChildrenPerInnerNode).FillWithZeroes();});
+    }
 
+    uint64_t maxChildrenPerInnerNode = nodeStore->layout().maxChildrenPerInnerNode();
 };
 
 TEST_F(DataTreeTest_Performance, DeletingDoesntLoadLeaves_Twolevel_DeleteByTree) {
-    auto key = this->CreateFullTwoLevel()->key();
-    auto tree = this->treeStore.load(key).value();
-    this->treeStore.remove(std::move(tree));
-    EXPECT_EQ(2u, blockStore->loadedBlocks.size());
+    auto key = CreateFullTwoLevel()->key();
+    auto tree = treeStore.load(key).value();
+    blockStore->resetCounters();
+
+    treeStore.remove(std::move(tree));
+
+    EXPECT_EQ(1u, blockStore->loadedBlocks.size()); // First loading is from loading the tree, second one from removing it (i.e. loading the root)
+    EXPECT_EQ(0u, blockStore->createdBlocks);
 }
 
 TEST_F(DataTreeTest_Performance, DeletingDoesntLoadLeaves_Twolevel_DeleteByKey) {
-    auto key = this->CreateFullTwoLevel()->key();
-    this->treeStore.remove(key);
+    auto key = CreateFullTwoLevel()->key();
+    blockStore->resetCounters();
+
+    treeStore.remove(key);
+
     EXPECT_EQ(1u, blockStore->loadedBlocks.size());
+    EXPECT_EQ(0u, blockStore->createdBlocks);
 }
 
 TEST_F(DataTreeTest_Performance, DeletingDoesntLoadLeaves_Threelevel_DeleteByTree) {
-    auto key = this->CreateFullThreeLevel()->key();
-    auto tree = this->treeStore.load(key).value();
-    this->treeStore.remove(std::move(tree));
-    EXPECT_EQ(2u + nodeStore->layout().maxChildrenPerInnerNode(), blockStore->loadedBlocks.size());
+    auto key = CreateFullThreeLevel()->key();
+    auto tree = treeStore.load(key).value();
+    blockStore->resetCounters();
+
+    treeStore.remove(std::move(tree));
+
+    EXPECT_EQ(1u + maxChildrenPerInnerNode, blockStore->loadedBlocks.size());
+    EXPECT_EQ(0u, blockStore->createdBlocks);
 }
 
 TEST_F(DataTreeTest_Performance, DeletingDoesntLoadLeaves_Threelevel_DeleteByKey) {
-    auto key = this->CreateFullThreeLevel()->key();
-    this->treeStore.remove(key);
-    EXPECT_EQ(1u + nodeStore->layout().maxChildrenPerInnerNode(), blockStore->loadedBlocks.size());
-}
\ No newline at end of file
+    auto key = CreateFullThreeLevel()->key();
+    blockStore->resetCounters();
+
+    treeStore.remove(key);
+
+    EXPECT_EQ(1u + maxChildrenPerInnerNode, blockStore->loadedBlocks.size());
+    EXPECT_EQ(0u, blockStore->createdBlocks);
+}
+
+TEST_F(DataTreeTest_Performance, TraverseLeaves_Twolevel_All) {
+    auto key = CreateFullTwoLevel()->key();
+    auto tree = treeStore.load(key).value();
+    blockStore->resetCounters();
+
+    Traverse(tree.get(), 0, maxChildrenPerInnerNode);
+
+    EXPECT_EQ(maxChildrenPerInnerNode, blockStore->loadedBlocks.size()); // Loads all leaves (not the root, because it is already loaded in the tree)
+    EXPECT_EQ(0u, blockStore->createdBlocks);
+}
+
+TEST_F(DataTreeTest_Performance, TraverseLeaves_Twolevel_Some) {
+    auto key = CreateFullTwoLevel()->key();
+    auto tree = treeStore.load(key).value();
+    blockStore->resetCounters();
+
+    Traverse(tree.get(), 3, 5);
+
+    EXPECT_EQ(2u, blockStore->loadedBlocks.size()); // Loads both leaves (not the root, because it is already loaded in the tree)
+    EXPECT_EQ(0u, blockStore->createdBlocks);
+}
+
+TEST_F(DataTreeTest_Performance, TraverseLeaves_Threelevel_All) {
+    auto key = CreateFullThreeLevel()->key();
+    auto tree = treeStore.load(key).value();
+    blockStore->resetCounters();
+
+    Traverse(tree.get(), 0, maxChildrenPerInnerNode * maxChildrenPerInnerNode);
+
+    EXPECT_EQ(maxChildrenPerInnerNode + maxChildrenPerInnerNode * maxChildrenPerInnerNode, blockStore->loadedBlocks.size()); // Loads inner nodes and all leaves once (not the root, because it is already loaded in the tree)
+    EXPECT_EQ(0u, blockStore->createdBlocks);
+}
+
+TEST_F(DataTreeTest_Performance, TraverseLeaves_Threelevel_InOneInner) {
+    auto key = CreateFullThreeLevel()->key();
+    auto tree = treeStore.load(key).value();
+    blockStore->resetCounters();
+
+    Traverse(tree.get(), 3, 5);
+
+    EXPECT_EQ(3u, blockStore->loadedBlocks.size()); // Loads inner node and both leaves (not the root, because it is already loaded in the tree)
+    EXPECT_EQ(0u, blockStore->createdBlocks);
+}
+
+TEST_F(DataTreeTest_Performance, TraverseLeaves_Threelevel_InTwoInner) {
+    auto key = CreateFullThreeLevel()->key();
+    auto tree = treeStore.load(key).value();
+    blockStore->resetCounters();
+
+    Traverse(tree.get(), 3, 3 + maxChildrenPerInnerNode);
+
+    EXPECT_EQ(2u + maxChildrenPerInnerNode, blockStore->loadedBlocks.size()); // Loads inner node and both leaves (not the root, because it is already loaded in the tree)
+    EXPECT_EQ(0u, blockStore->createdBlocks);
+}
+
+TEST_F(DataTreeTest_Performance, TraverseLeaves_Threelevel_WholeInner) {
+    auto key = CreateFullThreeLevel()->key();
+    auto tree = treeStore.load(key).value();
+    blockStore->resetCounters();
+
+    Traverse(tree.get(), maxChildrenPerInnerNode, 2*maxChildrenPerInnerNode);
+
+    EXPECT_EQ(1u + maxChildrenPerInnerNode, blockStore->loadedBlocks.size()); // Loads inner node and leaves (not the root, because it is already loaded in the tree)f
+    EXPECT_EQ(0u, blockStore->createdBlocks);
+}
+
+TEST_F(DataTreeTest_Performance, TraverseLeaves_GrowingTree_StartingInside) {
+    auto key = CreateInner({CreateLeaf(), CreateLeaf()})->key();
+    auto tree = treeStore.load(key).value();
+    blockStore->resetCounters();
+
+    Traverse(tree.get(), 1, 4);
+
+    EXPECT_EQ(1u, blockStore->loadedBlocks.size()); // Loads last old child (for growing it)
+    EXPECT_EQ(2u, blockStore->createdBlocks);
+}
+
+TEST_F(DataTreeTest_Performance, TraverseLeaves_GrowingTree_StartingOutside_TwoLevel) {
+    auto key = CreateInner({CreateLeaf(), CreateLeaf()})->key();
+    auto tree = treeStore.load(key).value();
+    blockStore->resetCounters();
+
+    Traverse(tree.get(), 4, 5);
+
+    EXPECT_EQ(1u, blockStore->loadedBlocks.size()); // Loads last old leaf for growing it
+    EXPECT_EQ(3u, blockStore->createdBlocks);
+}
+
+TEST_F(DataTreeTest_Performance, TraverseLeaves_GrowingTree_StartingOutside_ThreeLevel) {
+    auto key = CreateInner({CreateFullTwoLevel(), CreateFullTwoLevel()})->key();
+    auto tree = treeStore.load(key).value();
+    blockStore->resetCounters();
+
+    Traverse(tree.get(), 2*maxChildrenPerInnerNode+1, 2*maxChildrenPerInnerNode+2);
+
+    EXPECT_EQ(2u, blockStore->loadedBlocks.size()); // Loads last old leaf (and its inner node) for growing it
+    EXPECT_EQ(3u, blockStore->createdBlocks); // inner node and two leaves
+}
+
+TEST_F(DataTreeTest_Performance, TraverseLeaves_GrowingTree_StartingAtBeginOfChild) {
+    auto key = CreateInner({CreateFullTwoLevel(), CreateFullTwoLevel()})->key();
+    auto tree = treeStore.load(key).value();
+    blockStore->resetCounters();
+
+    Traverse(tree.get(), maxChildrenPerInnerNode, 3*maxChildrenPerInnerNode);
+
+    EXPECT_EQ(1u + maxChildrenPerInnerNode, blockStore->loadedBlocks.size()); // Inner node and its leaves
+    EXPECT_EQ(1u + maxChildrenPerInnerNode, blockStore->createdBlocks); // Creates an inner node and its leaves
+}
+
+TEST_F(DataTreeTest_Performance, TraverseLeaves_GrowingTreeDepth_StartingInOldDepth) {
+    auto key = CreateInner({CreateLeaf(), CreateLeaf()})->key();
+    auto tree = treeStore.load(key).value();
+    blockStore->resetCounters();
+
+    Traverse(tree.get(), 4, maxChildrenPerInnerNode+2);
+
+    EXPECT_EQ(1u, blockStore->loadedBlocks.size()); // Loads last old leaf for growing it
+    EXPECT_EQ(2 + maxChildrenPerInnerNode, blockStore->createdBlocks); // 2x new inner node + leaves
+}
+
+TEST_F(DataTreeTest_Performance, TraverseLeaves_GrowingTreeDepth_StartingInNewDepth) {
+    auto key = CreateInner({CreateLeaf(), CreateLeaf()})->key();
+    auto tree = treeStore.load(key).value();
+    blockStore->resetCounters();
+
+    Traverse(tree.get(), maxChildrenPerInnerNode, maxChildrenPerInnerNode+2);
+
+    EXPECT_EQ(1u, blockStore->loadedBlocks.size()); // Loads last old leaf for growing it
+    EXPECT_EQ(2 + maxChildrenPerInnerNode, blockStore->createdBlocks); // 2x new inner node + leaves
+}
diff --git a/test/blobstore/implementations/onblocks/datatreestore/testutils/MockBlockStore.h b/test/blobstore/implementations/onblocks/datatreestore/testutils/MockBlockStore.h
index 9e3a9f01..c89bf9a4 100644
--- a/test/blobstore/implementations/onblocks/datatreestore/testutils/MockBlockStore.h
+++ b/test/blobstore/implementations/onblocks/datatreestore/testutils/MockBlockStore.h
@@ -9,7 +9,7 @@
 class MockBlockStore final : public blockstore::BlockStore {
 public:
     MockBlockStore(cpputils::unique_ref<BlockStore> baseBlockStore = cpputils::make_unique_ref<blockstore::testfake::FakeBlockStore>())
-        : _baseBlockStore(std::move(baseBlockStore)) {
+        : loadedBlocks(), createdBlocks(0), _mutex(), _baseBlockStore(std::move(baseBlockStore)) {
     }
 
     blockstore::Key createKey() override {
@@ -17,6 +17,10 @@ public:
     }
 
     boost::optional<cpputils::unique_ref<blockstore::Block>> tryCreate(const blockstore::Key &key, cpputils::Data data) override {
+        {
+            std::unique_lock<std::mutex> lock(_mutex);
+            createdBlocks += 1;
+        }
         return _baseBlockStore->tryCreate(key, std::move(data));
     }
 
@@ -52,7 +56,13 @@ public:
         return _baseBlockStore->remove(std::move(block));
     }
 
+    void resetCounters() {
+        loadedBlocks = {};
+        createdBlocks = 0;
+    }
+
     std::vector<blockstore::Key> loadedBlocks;
+    uint64_t createdBlocks;
 
 private:
     std::mutex _mutex;