Wait for nodes to discover each other in test_action_graph.py (#354)
Wait for nodes to discover each other in test_action_graph.py (#354)

* Wait for nodes to discover each other in test_action_graph.py

Signed-off-by: Michel Hidalgo <2c7f9fd20fbeb41ce8894ec4653d66fa7f3b6e1a@ekumenlabs.com>

* Address peer review comments.

Signed-off-by: Michel Hidalgo <2c7f9fd20fbeb41ce8894ec4653d66fa7f3b6e1a@ekumenlabs.com>

ros2/rclpy,ros2/rclpy