Added printTreeRecursively overload with ostream parameter

include/behaviortree_cpp_v3/behavior_tree.h

@@ -44,6 +44,7 @@
 #include "behaviortree_cpp_v3/decorators/timeout_node.h"
 #include "behaviortree_cpp_v3/decorators/delay_node.h"
 
+#include <iostream>
 
 namespace BT
 {
@@ -56,9 +57,9 @@ void applyRecursiveVisitor(const TreeNode* root_node,
 void applyRecursiveVisitor(TreeNode* root_node, const std::function<void(TreeNode*)>& visitor);
 
 /**
- * Debug function to print on screen the hierarchy of the tree.
+ * Debug function to print the hierarchy of the tree. Prints to std::cout by default.
  */
-void printTreeRecursively(const TreeNode* root_node);
+void printTreeRecursively(const TreeNode* root_node, std::ostream& stream = std::cout);
 
 typedef std::vector<std::pair<uint16_t, uint8_t>> SerializedTreeStatus;
 

src/behavior_tree.cpp

@@ -60,21 +60,21 @@ void applyRecursiveVisitor(TreeNode* node, const std::function<void(TreeNode*)>&
     }
 }
 
-void printTreeRecursively(const TreeNode* root_node)
+void printTreeRecursively(const TreeNode* root_node, std::ostream& stream)
 {
     std::function<void(unsigned, const BT::TreeNode*)> recursivePrint;
 
-    recursivePrint = [&recursivePrint](unsigned indent, const BT::TreeNode* node) {
+    recursivePrint = [&recursivePrint, &stream](unsigned indent, const BT::TreeNode* node) {
         for (unsigned i = 0; i < indent; i++)
         {
-            std::cout << "   ";
+            stream << "   ";
         }
         if (!node)
         {
-            std::cout << "!nullptr!" << std::endl;
+            stream << "!nullptr!" << std::endl;
             return;
         }
-        std::cout << node->name() << std::endl;
+        stream << node->name() << std::endl;
         indent++;
 
         if (auto control = dynamic_cast<const BT::ControlNode*>(node))
@@ -90,9 +90,9 @@ void printTreeRecursively(const TreeNode* root_node)
         }
     };
 
-    std::cout << "----------------" << std::endl;
+    stream << "----------------" << std::endl;
     recursivePrint(0, root_node);
-    std::cout << "----------------" << std::endl;
+    stream << "----------------" << std::endl;
 }
 
 void buildSerializedStatusSnapshot(TreeNode* root_node, SerializedTreeStatus& serialized_buffer)

tests/gtest_tree.cpp

@@ -15,6 +15,9 @@
 #include "condition_test_node.h"
 #include "behaviortree_cpp_v3/behavior_tree.h"
 
+#include <sstream>
+#include <string>
+
 using BT::NodeStatus;
 using std::chrono::milliseconds;
 
@@ -76,6 +79,45 @@ TEST_F(BehaviorTreeTest, Condition2ToFalseCondition1True)
     ASSERT_EQ(NodeStatus::RUNNING, action_1.status());
 }
 
+TEST_F(BehaviorTreeTest, PrintWithStream)
+{
+    // no stream parameter should go to default stream (std::cout)
+    BT::printTreeRecursively(&root);
+
+    // verify value for with custom stream parameter
+    std::stringstream stream;
+    BT::printTreeRecursively(&root, stream);
+    const auto string = stream.str();
+    std::string line;
+
+    // first line is all dashes
+    ASSERT_FALSE(std::getline(stream, line, '\n').fail());
+    ASSERT_STREQ("----------------", line.c_str());
+
+    // each line is the name of the node, indented by depth * 3 spaces
+    ASSERT_FALSE(std::getline(stream, line, '\n').fail());
+    ASSERT_STREQ(root.name().c_str(), line.c_str());
+
+    ASSERT_FALSE(std::getline(stream, line, '\n').fail());
+    ASSERT_STREQ(("   " + fal_conditions.name()).c_str(), line.c_str());
+
+    ASSERT_FALSE(std::getline(stream, line, '\n').fail());
+    ASSERT_STREQ(("      " + condition_1.name()).c_str(), line.c_str());
+
+    ASSERT_FALSE(std::getline(stream, line, '\n').fail());
+    ASSERT_STREQ(("      " + condition_2.name()).c_str(), line.c_str());
+
+    ASSERT_FALSE(std::getline(stream, line, '\n').fail());
+    ASSERT_STREQ(("   " + action_1.name()).c_str(), line.c_str());
+
+    // last line is all dashes
+    ASSERT_FALSE(std::getline(stream, line, '\n').fail());
+    ASSERT_STREQ("----------------", line.c_str());
+
+    // no more lines
+    ASSERT_TRUE(std::getline(stream, line, '\n').fail());
+}
+
 int main(int argc, char** argv)
 {
     testing::InitGoogleTest(&argc, argv);