Sandbox environment in tests to fix repeated job failures (#609)

Signed-off-by: Shane Loretz <[email protected]>

Author: sloretz

launch/test/launch/actions/test_append_environment_variable.py

@@ -21,7 +21,10 @@
 from launch.substitutions import EnvironmentVariable
 from launch.substitutions import TextSubstitution
 
+from temporary_environment import sandbox_environment_variables
 
+
+@sandbox_environment_variables
 def test_append_environment_variable_constructor():
     """Test the constructor for the AppendEnvironmentVariable class."""
     AppendEnvironmentVariable('name', 'value')
@@ -31,6 +34,7 @@ def test_append_environment_variable_constructor():
     AppendEnvironmentVariable('name', 'value', prepend=True, separator='|')
 
 
+@sandbox_environment_variables
 def test_append_environment_variable_execute():
     """Test the execute() of the AppendEnvironmentVariable class."""
     context = LaunchContext()

launch/test/launch/actions/test_group_action.py

@@ -26,6 +26,8 @@
 from launch.actions import SetLaunchConfiguration
 from launch.substitutions import LaunchConfiguration
 
+from temporary_environment import sandbox_environment_variables
+
 
 def test_group_action_constructors():
     """Test the constructors for the GroupAction class."""
@@ -36,6 +38,7 @@ def test_group_action_constructors():
     GroupAction([Action()], scoped=False, forwarding=False, launch_configurations={'foo': 'FOO'})
 
 
+@sandbox_environment_variables
 def test_group_action_execute():
     """Test the execute() of the the GroupAction class."""
     lc1 = LaunchContext()

launch/test/launch/actions/test_set_and_unset_environment_variable.py

@@ -19,13 +19,17 @@
 from launch.actions import UnsetEnvironmentVariable
 from launch.substitutions import EnvironmentVariable
 
+from temporary_environment import sandbox_environment_variables
 
+
+@sandbox_environment_variables
 def test_set_and_unset_environment_variable_constructors():
     """Test the constructor for SetEnvironmentVariable and UnsetEnvironmentVariable classes."""
     SetEnvironmentVariable('name', 'value')
     UnsetEnvironmentVariable('name')
 
 
+@sandbox_environment_variables
 def test_set_and_unset_environment_variable_execute():
     """Test the execute() of the SetEnvironmentVariable and UnsetEnvironmentVariable classes."""
     context = LaunchContext()

launch/test/temporary_environment.py

@@ -0,0 +1,49 @@
+# Copyright 2022 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.
+
+import functools
+import os
+
+
+class TemporaryEnvironment:
+    """Allow temporary changes to environment variables."""
+
+    def __init__(self):
+        self.__old_env = None
+
+    def __enter__(self):
+        self.__old_env = os.environ.copy()
+        return self
+
+    def __exit__(self, t, v, tb):
+        # Update keys manually to make sure putenv gets called
+        for key, value in self.__old_env.items():
+            os.environ[key] = value
+        # Remove added keys
+        env_keys = tuple(os.environ)
+        for key in env_keys:
+            if key not in self.__old_env:
+                del os.environ[key]
+        self.__old_env = None
+
+
+def sandbox_environment_variables(func):
+    """Decorate a function to give it a temporary environment."""
+
+    @functools.wraps(func)
+    def wrapper_func(*args, **kwargs):
+        with TemporaryEnvironment():
+            func(*args, **kwargs)
+
+    return wrapper_func