Support launch_ros test runner in pytest (#54)

* Support launch_ros test runner in pytest.

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

* Test examples using pytest

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

* Improve pytest rostest marker documentation.

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

* Move examples README to the root.

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

* Remove single marker constraint for generate_test_description functions.

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

* Please flake8

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

* Install examples properly.

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

launch_testing_ros/README.md

@@ -0,0 +1,28 @@
+# launch\_testing\_ros
+
+## Examples
+
+### `talker_listener_launch_test.py`
+
+Usage:
+
+```sh
+launch_test test/examples/talker_listener_launch_test.py
+```
+
+This test launches the talker and listener example nodes from demo\_nodes\_py and interacts
+with them via their ROS interfaces.  Remapping rules are used so that one of the tests can sit in
+between the talker and the listener and change the data on the fly.
+
+#### test\_fuzzy\_data
+This test gives an example of what a test that fuzzes data might look like.  A ROS subscriber
+and publisher pair encapsulated in a `DataRepublisher` object changes the string "Hello World" to
+"Aloha World" as it travels between the talker and the listener.
+
+#### test\_listener\_receives
+This test publishes unique messages on the `/chatter` topic and asserts that the same messages
+go to the stdout of the listener node
+
+#### test\_talker\_transmits
+This test subscribes to the remapped `/talker_chatter` topic and makes sure the talker node also
+writes the data it's transmitting to stdout

launch_testing_ros/launch_testing_ros/pytest/hooks.py

@@ -0,0 +1,43 @@
+# Copyright 2019 Open Source Robotics Foundation, Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from launch_testing.pytest.hooks import LaunchTestItem
+from launch_testing.pytest.hooks import LaunchTestModule
+
+from ..test_runner import LaunchTestRunner
+
+
+class LaunchROSTestItem(LaunchTestItem):
+
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs, runner_cls=LaunchTestRunner)
+
+
+class LaunchROSTestModule(LaunchTestModule):
+
+    def makeitem(self, *args, **kwargs):
+        return LaunchROSTestItem(*args, **kwargs)
+
+
+def pytest_launch_collect_makemodule(path, parent, entrypoint):
+    marks = getattr(entrypoint, 'pytestmark', [])
+    if marks and any(m.name == 'rostest' for m in marks):
+        return LaunchROSTestModule(path, parent)
+
+
+def pytest_configure(config):
+    config.addinivalue_line(
+        'markers',
+        'rostest: mark a generate_test_description function as a ROS launch test entrypoint'
+    )

launch_testing_ros/setup.py

@@ -10,8 +10,11 @@
     data_files=[
         ('share/ament_index/resource_index/packages', ['resource/launch_testing_ros']),
         ('lib/launch_testing_ros', glob.glob('example_nodes/**')),
-        ('share/launch_testing_ros/examples', glob.glob('examples/[!_]**')),
+        ('share/launch_testing_ros/examples', glob.glob('test/examples/[!_]**')),
     ],
+    entry_points={
+        'pytest11': ['launch_ros = launch_testing_ros.pytest.hooks'],
+    },
     install_requires=['setuptools'],
     zip_safe=True,
     author='Pete Baughman',