Fix use of mutable default arg in tracetools_test (#84)

Signed-off-by: Christophe Bedard <[email protected]>

tracetools_test/tracetools_test/case.py

@@ -62,7 +62,7 @@ def __init__(
         nodes: List[str],
         base_path: str = '/tmp',
         events_kernel: List[str] = [],
-        additional_actions: Union[List[Action], Action] = [],
+        additional_actions: Optional[List[Action]] = None,
     ) -> None:
         """Create a TraceTestCase."""
         super().__init__(methodName=args[0])
@@ -72,7 +72,7 @@ def __init__(
         self._events_kernel = events_kernel
         self._package = package
         self._nodes = nodes
-        self._additional_actions = additional_actions
+        self._additional_actions = additional_actions or []
 
     def setUp(self):
         # Get timestamp before trace (ns)

tracetools_test/tracetools_test/utils.py

@@ -18,7 +18,6 @@
 import shutil
 from typing import List
 from typing import Tuple
-from typing import Union
 
 from launch import Action
 from launch import LaunchDescription
@@ -37,7 +36,7 @@ def run_and_trace(
     kernel_events: List[str],
     package_name: str,
     node_names: List[str],
-    additional_actions: Union[List[Action], Action] = [],
+    additional_actions: List[Action],
 ) -> Tuple[int, str]:
     """
     Run a node while tracing.
@@ -48,15 +47,13 @@ def run_and_trace(
     :param kernel_events: the list of kernel events to enable
     :param package_name: the name of the package to use
     :param node_names: the names of the nodes to execute
-    :param additional_actions: the list of additional actions to prepend
+    :param additional_actions: the list of additional actions to append
     :return: exit code, full generated path
     """
     session_name = append_timestamp(session_name_prefix)
     full_path = os.path.join(base_path, session_name)
-    if not isinstance(additional_actions, list):
-        additional_actions = [additional_actions]
 
-    launch_actions = additional_actions
+    launch_actions = []
     # Add trace action
     launch_actions.append(
         Trace(
@@ -75,6 +72,7 @@ def run_and_trace(
             output='screen',
         )
         launch_actions.append(n)
+    launch_actions.extend(additional_actions)
     ld = LaunchDescription(launch_actions)
     ls = LaunchService()
     ls.include_launch_description(ld)