diff --git a/tracetools_test/CMakeLists.txt b/tracetools_test/CMakeLists.txt
index b0ee45f..4690fb8 100644
--- a/tracetools_test/CMakeLists.txt
+++ b/tracetools_test/CMakeLists.txt
@@ -30,10 +30,26 @@ if(BUILD_TESTING)
     rclcpp
     std_msgs
   )
+  add_executable(test_ping
+    src/test_ping.cpp
+  )
+  ament_target_dependencies(test_ping
+    rclcpp
+    std_msgs
+  )
+  add_executable(test_pong
+    src/test_pong.cpp
+  )
+  ament_target_dependencies(test_pong
+    rclcpp
+    std_msgs
+  )
 
   install(TARGETS
     test_publisher
     test_subscription
+    test_ping
+    test_pong
     DESTINATION lib/${PROJECT_NAME}
   )
 
diff --git a/tracetools_test/src/test_ping.cpp b/tracetools_test/src/test_ping.cpp
new file mode 100644
index 0000000..611afeb
--- /dev/null
+++ b/tracetools_test/src/test_ping.cpp
@@ -0,0 +1,62 @@
+#include <memory>
+#include <chrono>
+
+#include "rclcpp/rclcpp.hpp"
+#include "rclcpp/rate.hpp"
+#include "std_msgs/msg/string.hpp"
+
+using namespace std::chrono_literals;
+
+
+class PingNode : public rclcpp::Node
+{
+public:
+    PingNode(rclcpp::NodeOptions options) : Node("ping_node", options)
+    {
+        sub_ = this->create_subscription<std_msgs::msg::String>(
+            "pong",
+            rclcpp::QoS(10),
+            std::bind(&PingNode::callback, this, std::placeholders::_1));
+        pub_ = this->create_publisher<std_msgs::msg::String>(
+            "ping",
+            rclcpp::QoS(10));
+        timer_ = this->create_wall_timer(
+            500ms,
+            std::bind(&PingNode::timer_callback, this));
+    }
+
+
+private:
+    void callback(const std_msgs::msg::String::SharedPtr msg)
+    {
+        RCLCPP_INFO(this->get_logger(), "[output] %s", msg->data.c_str());
+        rclcpp::shutdown();
+    }
+
+    void timer_callback()
+    {
+        auto msg = std::make_shared<std_msgs::msg::String>();
+        msg->data = "some random ping string";
+        pub_->publish(*msg);
+    }
+
+    rclcpp::Subscription<std_msgs::msg::String>::SharedPtr sub_;
+    rclcpp::Publisher<std_msgs::msg::String>::SharedPtr pub_;
+    rclcpp::TimerBase::SharedPtr timer_;
+};
+
+int main(int argc, char* argv[])
+{
+    rclcpp::init(argc, argv);
+
+    rclcpp::executors::SingleThreadedExecutor exec;
+    auto ping_node = std::make_shared<PingNode>(rclcpp::NodeOptions());
+    exec.add_node(ping_node);
+
+    printf("spinning\n");
+    exec.spin();
+
+    // Will actually be called inside the node's callback
+    rclcpp::shutdown();
+    return 0;
+}
diff --git a/tracetools_test/src/test_pong.cpp b/tracetools_test/src/test_pong.cpp
new file mode 100644
index 0000000..99e35ce
--- /dev/null
+++ b/tracetools_test/src/test_pong.cpp
@@ -0,0 +1,49 @@
+#include <memory>
+
+#include "rclcpp/rclcpp.hpp"
+#include "std_msgs/msg/string.hpp"
+
+
+class PongNode : public rclcpp::Node
+{
+public:
+    PongNode(rclcpp::NodeOptions options) : Node("pong_node", options)
+    {
+        sub_ = this->create_subscription<std_msgs::msg::String>(
+            "ping",
+            rclcpp::QoS(10),
+            std::bind(&PongNode::callback, this, std::placeholders::_1));
+        pub_ = this->create_publisher<std_msgs::msg::String>(
+            "pong",
+            rclcpp::QoS(10));
+    }
+
+private:
+    void callback(const std_msgs::msg::String::SharedPtr msg)
+    {
+        RCLCPP_INFO(this->get_logger(), "[output] %s", msg->data.c_str());
+        auto next_msg = std::make_shared<std_msgs::msg::String>();
+        next_msg->data = "some random pong string";
+        pub_->publish(*next_msg);
+        rclcpp::shutdown();
+    }
+
+    rclcpp::Subscription<std_msgs::msg::String>::SharedPtr sub_;
+    rclcpp::Publisher<std_msgs::msg::String>::SharedPtr pub_;
+};
+
+int main(int argc, char* argv[])
+{
+    rclcpp::init(argc, argv);
+
+    rclcpp::executors::SingleThreadedExecutor exec;
+    auto pong_node = std::make_shared<PongNode>(rclcpp::NodeOptions());
+    exec.add_node(pong_node);
+
+    printf("spinning\n");
+    exec.spin();
+
+    // Will actually be called inside the node's callback
+    rclcpp::shutdown();
+    return 0;
+}
diff --git a/tracetools_test/test/test_node.py b/tracetools_test/test/test_node.py
index 2757948..cd25e4a 100644
--- a/tracetools_test/test/test_node.py
+++ b/tracetools_test/test/test_node.py
@@ -17,7 +17,7 @@ class TestNode(unittest.TestCase):
     def test_creation(self):
         session_name_prefix = 'session-test-node-creation'
         base_path = '/tmp'
-        test_node = 'test_publisher'
+        test_node = ['test_publisher']
 
         exit_code, full_path = run_and_trace(base_path, session_name_prefix, node_creation_events, None, PKG, test_node)
         self.assertEqual(exit_code, 0)
diff --git a/tracetools_test/test/test_publisher.py b/tracetools_test/test/test_publisher.py
index 0c15283..e2ce3d0 100644
--- a/tracetools_test/test/test_publisher.py
+++ b/tracetools_test/test/test_publisher.py
@@ -16,7 +16,7 @@ class TestPublisher(unittest.TestCase):
     def test_creation(self):
         session_name_prefix = 'session-test-publisher-creation'
         base_path = '/tmp'
-        test_node = 'test_publisher'
+        test_node = ['test_publisher']
 
         exit_code, full_path = run_and_trace(base_path, session_name_prefix, publisher_creation_events, None, PKG, test_node)
         self.assertEqual(exit_code, 0)
diff --git a/tracetools_test/test/test_subscription.py b/tracetools_test/test/test_subscription.py
index 5caac19..693ba85 100644
--- a/tracetools_test/test/test_subscription.py
+++ b/tracetools_test/test/test_subscription.py
@@ -12,12 +12,17 @@ subscription_creation_events = [
     'ros2:rclcpp_subscription_callback_added',
 ]
 
+subscription_callback_events = [
+    'ros2:rclcpp_subscription_callback_start',
+    'ros2:rclcpp_subscription_callback_end',
+]
+
 class TestSubscription(unittest.TestCase):
 
     def test_creation(self):
         session_name_prefix = 'session-test-subscription-creation'
         base_path = '/tmp'
-        test_node = 'test_subscription'
+        test_node = ['test_subscription']
 
         exit_code, full_path = run_and_trace(base_path, session_name_prefix, subscription_creation_events, None, PKG, test_node)
         self.assertEqual(exit_code, 0)
@@ -28,6 +33,20 @@ class TestSubscription(unittest.TestCase):
 
         cleanup_trace(full_path)
 
+    def test_callback(self):
+        session_name_prefix = 'session-test-subscription-callback'
+        base_path = '/tmp'
+        test_nodes = ['test_ping', 'test_pong']
+
+        exit_code, full_path = run_and_trace(base_path, session_name_prefix, subscription_callback_events, None, PKG, test_nodes)
+        self.assertEqual(exit_code, 0)
+
+        trace_events = get_trace_event_names(full_path)
+        print(f'trace_events: {trace_events}')
+        self.assertSetEqual(set(subscription_callback_events), trace_events)
+
+        cleanup_trace(full_path)
+
 
 if __name__ == '__main__':
     unittest.main()
diff --git a/tracetools_test/tracetools_test/utils.py b/tracetools_test/tracetools_test/utils.py
index f104867..462cb23 100644
--- a/tracetools_test/tracetools_test/utils.py
+++ b/tracetools_test/tracetools_test/utils.py
@@ -15,7 +15,7 @@ from tracetools_trace.tools.lttng import (
     lttng_destroy,
 )
 
-def run_and_trace(base_path, session_name_prefix, ros_events, kernel_events, package_name, node_executable):
+def run_and_trace(base_path, session_name_prefix, ros_events, kernel_events, package_name, node_names):
     """
     Run a node while tracing
     :param base_path (str): the base path where to put the trace directory
@@ -23,7 +23,7 @@ def run_and_trace(base_path, session_name_prefix, ros_events, kernel_events, pac
     :param ros_events (list(str)): the list of ROS UST events to enable
     :param kernel_events (list(str)): the list of kernel events to enable
     :param package_name (str): the name of the package to use
-    :param node_executable (str): the name of the node to execute
+    :param node_names (list(str)): the names of the nodes to execute
     """
     session_name = f'{session_name_prefix}-{time.strftime("%Y%m%d%H%M%S")}'
     full_path = f'{base_path}/{session_name}'
@@ -32,10 +32,13 @@ def run_and_trace(base_path, session_name_prefix, ros_events, kernel_events, pac
     lttng_setup(session_name, full_path, ros_events=ros_events, kernel_events=kernel_events)
     lttng_start(session_name)
 
-    ld = LaunchDescription([
-        launch_ros.actions.Node(
-            package=package_name, node_executable=node_executable, output='screen'),
-    ])
+    nodes = []
+    for node_name in node_names:
+        n = launch_ros.actions.Node(package=package_name,
+                                    node_executable=node_name,
+                                    output='screen')
+        nodes.append(n)
+    ld = LaunchDescription(nodes)
     ls = LaunchService()
     ls.include_launch_description(get_default_launch_description())
     ls.include_launch_description(ld)