text: def test_spawn(hlwm, hlwm_process):
      with hlwm_process.wait_stderr_match('spawnyboi'):
          cmd = ['spawn', 'sh', '-c', 'echo >&2 spawnyboi']
          proc = hlwm.unchecked_call(cmd, read_hlwm_output=False)
          assert proc.returncode == 0
          assert not proc.stderr
          assert not proc.stdout
  