source/blender/blenkernel/CMakeLists.txt

@@ -841,6 +841,7 @@ if(WITH_GTESTS)
     intern/lib_remap_test.cc
     intern/nla_test.cc
     intern/tracking_test.cc
+    intern/grease_pencil_test.cc
   )
   set(TEST_INC
     ../editors/include

source/blender/blenkernel/intern/grease_pencil_test.cc

@@ -0,0 +1,28 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later
+ * Copyright 2021 Blender Foundation. */
+
+#include "testing/testing.h"
+
+#include "BKE_grease_pencil.hh"
+
+using namespace blender::bke::gpencil;
+
+namespace blender::bke::gpencil::tests {
+
+TEST(gpencil, build_layer_tree)
+{
+  TreeNode root{};
+  
+  TreeNode node("Node1");
+  node.add_child(TreeNode("Child1"));
+  node.add_child(TreeNode("Child2"));
+  
+  root.add_child(std::move(node));
+  root.add_child(TreeNode("Node2"));
+
+  for (TreeNode &node : root.children_in_pre_order()) {
+    std::cout << node.name << std::endl;
+  }
+}
+
+}  // namespace blender::bke::gpencil::tests