def test__read_stdout():
    from rospkg.os_detect import _read_stdout
    assert 'hello' == _read_stdout(['echo', 'hello'])
    assert None == _read_stdout(['bad-command-input-for-rospkg-os-detect'])
def test__read_stdout():
    from rospkg.os_detect import _read_stdout
    assert 'hello' == _read_stdout(['echo', 'hello'])
    assert _read_stdout(['bad-command-input-for-rospkg-os-detect']) is None