launch environment passing fail

check_env.py

import os

print(os.environ.get('testenv2', 'Not Set'))
print(os.environ.get('testenv1', 'Not Set'))
assert(os.environ.get('testenv2', 'Not Set') == 'testval2')
assert(os.environ.get('testenv1', 'Not Set') == 'testval1')

test_env.py

import os
import sys

from launch import LaunchDescriptor
from launch.launcher import DefaultLauncher
from launch.exit_handler import primary_exit_handler


def test_env():
    ld = LaunchDescriptor()

    sub_env = dict(os.environ)
    sub_env['testenv1'] = 'testval1'
    os.environ['testenv2'] = 'testval2'
    ld.add_process(
        cmd=[sys.executable, '/home/mikael/work/ros2/ros2_ws/src/ros2/launch/launch_testing/test/check_env.py'],
        name='test_env',
        env=sub_env,
        exit_handler=primary_exit_handler,
    )
    launcher = DefaultLauncher()
    launcher.add_launch_descriptor(ld)
    rc = launcher.launch()

    assert rc == 0, \
        "The launch file failed with exit code '" + str(rc) + "'. "


if __name__ == '__main__':
    test_env()