Implement get_node_type_descriptions_interface for lifecyclenode and add smoke test for it (#2237)

Signed-off-by: Emerson Knapp <[email protected]>

Author: emersonknapp

rclcpp/test/rclcpp/test_node.cpp

@@ -78,6 +78,7 @@ TEST_F(TestNode, construction_and_destruction) {
     EXPECT_NE(nullptr, node->get_node_options().get_rcl_node_options());
     EXPECT_NE(nullptr, node->get_graph_event());
     EXPECT_NE(nullptr, node->get_clock());
+    EXPECT_NE(nullptr, node->get_node_type_descriptions_interface());
   }
 
   {

rclcpp_lifecycle/include/rclcpp_lifecycle/lifecycle_node.hpp

@@ -824,6 +824,10 @@ class LifecycleNode : public node_interfaces::LifecycleNodeInterface,
   rclcpp::node_interfaces::NodeTimeSourceInterface::SharedPtr
   get_node_time_source_interface();
 
+  /// Return the Node's internal NodeTypeDescriptionsInterface implementation.
+  /**
+   * \sa rclcpp::Node::get_node_type_descriptions_interface
+   */
   RCLCPP_LIFECYCLE_PUBLIC
   rclcpp::node_interfaces::NodeTypeDescriptionsInterface::SharedPtr
   get_node_type_descriptions_interface();

rclcpp_lifecycle/src/lifecycle_node.cpp

@@ -475,6 +475,12 @@ LifecycleNode::get_node_topics_interface()
   return node_topics_;
 }
 
+rclcpp::node_interfaces::NodeTypeDescriptionsInterface::SharedPtr
+LifecycleNode::get_node_type_descriptions_interface()
+{
+  return node_type_descriptions_;
+}
+
 rclcpp::node_interfaces::NodeServicesInterface::SharedPtr
 LifecycleNode::get_node_services_interface()
 {

rclcpp_lifecycle/test/test_lifecycle_node.cpp

@@ -641,6 +641,7 @@ TEST_F(TestDefaultStateMachine, test_getters) {
   EXPECT_LT(0u, test_node->now().nanoseconds());
   EXPECT_STREQ("testnode", test_node->get_logger().get_name());
   EXPECT_NE(nullptr, const_cast<const EmptyLifecycleNode *>(test_node.get())->get_clock());
+  EXPECT_NE(nullptr, test_node->get_node_type_descriptions_interface());
 }
 
 TEST_F(TestDefaultStateMachine, test_graph_topics) {