Mark launch tests explicitly.

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

launch_testing/launch_testing/pytest/hooks.py

@@ -99,17 +99,21 @@ def pytest_pycollect_makemodule(path, parent):
     entrypoint = find_launch_test_entrypoint(path)
     if entrypoint is not None:
         ihook = parent.session.gethookproxy(path)
-        return ihook.pytest_launch_collect_makemodule(
+        module = ihook.pytest_launch_collect_makemodule(
             path=path, parent=parent, entrypoint=entrypoint
         )
-    elif path.basename == '__init__.py':
+        if module is not None:
+            return module
+    if path.basename == '__init__.py':
         return pytest.Package(path, parent)
     return pytest.Module(path, parent)
 
 
 @pytest.hookimpl(trylast=True)
 def pytest_launch_collect_makemodule(path, parent, entrypoint):
-    return LaunchTestModule(path, parent)
+    marks = getattr(entrypoint, 'pytestmark', [])
+    if marks and any(m.name == 'launch_test' for m in marks):
+        return LaunchTestModule(path, parent)
 
 
 def pytest_addhooks(pluginmanager):
@@ -122,3 +126,9 @@ def pytest_addoption(parser):
         '--launch-args', action='append', nargs='*',
         default=[], help='One or more Launch test arguments'
     )
+
+
+def pytest_configure(config):
+    config.addinivalue_line(
+        'markers', 'launch_test: mark a generate_test_description function as a launch test entrypoint'
+    )

launch_testing/test/launch_testing/examples/args_launch_test.py

@@ -25,6 +25,9 @@
 import launch_testing
 import launch_testing.util
 
+import pytest
+
+
 dut_process = launch.actions.ExecuteProcess(
     cmd=[
         sys.executable,
@@ -40,6 +43,7 @@
 )
 
 
+@pytest.mark.launch_test
 def generate_test_description(ready_fn):
 
     return launch.LaunchDescription([

launch_testing/test/launch_testing/examples/context_launch_test.py

@@ -24,6 +24,8 @@
 import launch_testing
 from launch_testing.asserts import assertSequentialStdout
 
+import pytest
+
 
 def get_test_process_action():
     TEST_PROC_PATH = os.path.join(
@@ -42,6 +44,7 @@ def get_test_process_action():
 # This launch description shows the prefered way to let the tests access launch actions.  By
 # adding them to the test context, it's not necessary to scope them at the module level like in
 # the good_proc.test.py example
+@pytest.mark.launch_test
 def generate_test_description(ready_fn):
     dut_process = get_test_process_action()
 

launch_testing/test/launch_testing/examples/good_proc_launch_test.py

@@ -24,6 +24,8 @@
 import launch_testing
 from launch_testing.asserts import assertSequentialStdout
 
+import pytest
+
 
 TEST_PROC_PATH = os.path.join(
     ament_index_python.get_package_prefix('launch_testing'),
@@ -41,6 +43,7 @@
 )
 
 
+@pytest.mark.launch_test
 def generate_test_description(ready_fn):
 
     return launch.LaunchDescription([

launch_testing/test/launch_testing/examples/parameters_launch_test.py

@@ -23,7 +23,10 @@
 import launch_testing
 import launch_testing.util
 
+import pytest
 
+
+@pytest.mark.launch_test
 @launch_testing.parametrize('arg_param', ['thing=On', 'thing=Off', 'flag1'])
 def generate_test_description(arg_param, ready_fn):
 

launch_testing/test/launch_testing/examples/terminating_proc_launch_test.py

@@ -25,6 +25,8 @@
 import launch_testing.asserts
 import launch_testing.tools
 
+import pytest
+
 
 def get_test_process_action(*, args=[]):
     test_proc_path = os.path.join(
@@ -40,6 +42,7 @@ def get_test_process_action(*, args=[]):
     )
 
 
+@pytest.mark.launch_test
 def generate_test_description(ready_fn):
     return launch.LaunchDescription([
         launch_testing.util.KeepAliveProc(),