def test_cmd_mark_diff(curses_mock):
cmd1 = Command('test1', 1, Mock())
cmd2 = Command('test2', 2, Mock())
watch = Watch(Mock(height=20, width=80), Mock(), [cmd1, cmd2], Mock())
eq_(None, cmd1.mark)
cmd1.content = ['test\noutput\n']
rolex.cmd_mark_diff(watch, None)
eq_(['test', 'output'], cmd1.mark)
