Re: [Qemu-devel] [PATCH v5 0/3] Add common QEMU control functionality to qemu-iotests

[Stefan Hajnoczi]

On Wed, Apr 30, 2014 at 10:55:07AM -0400, Jeff Cody wrote:
> This adds some common functionality to control QEMU for qemu-iotests.
> 
> Additionally, test 085 is updated to use this new functionality.
> 
> Some minor fixups along the way, to clear up spaced pathname issues, 
> for common.rc, test 019, and test 086.
> 
> 
> Jeff Cody (3):
>   block: qemu-iotests - add common.qemu, for bash-controlled qemu tests

Once a test launches QEMU, it soon needs to parse QMP commands or wait
for QMP events.  That doesn't lend itself to the traditional
qemu-iotests shell model.  That is why iotests.py exists.

Shell script is a poor language for test cases that go beyond
pre-defined commands whose output is saved for diffing.  The string
manipulation is clumsy, JSON is not supported, tricks with fifos can
easily deadlock or break when a process terminates unexpectedly, etc.

If we go further in the direction of this patch series, we'll duplicate
existing iotests.py code and have complex shell tests that are hard to
extend.  I think it's time to draw the line and convert any test cases
that need to complexity to Python.

Why not use iotests.py?

Do you want help converting test cases that are on the edge to Python?

CCing Max because I think he was in favor of shell in the past and might
have some points here.