Test `apply command stack to playlist` without evaluating.
>>> stack = CommandStack([
-... CommandMessage('flat_filter_peaks --block retract --min_points 1'),
+... CommandMessage('flat filter peaks',
+... {'block':'retract', 'min points':1}),
... ])
>>> h.run_command('apply command stack to playlist',
... {'commands': stack, 'evaluate': False}
... print c # doctest: +ELLIPSIS, +NORMALIZE_WHITESPACE, +REPORT_UDIFF
<CommandMessage zero surface contact point
{..., curve: <Curve 20071120a_i27_t33.100>...}>
-<CommandMessage flat_filter_peaks --block retract --min_points 1>
+<CommandMessage flat filter peaks {block: retract, min points: 1}>
Test `clear curve command stack`.