Re: [PATCH 2/3] iotests: port 141 to Python for reliable QMP testing

[Kevin Wolf]

Am 16.01.2024 um 20:00 hat Stefan Hajnoczi geschrieben:
> The common.qemu bash functions allow tests to interact with the QMP
> monitor of a QEMU process. I spent two days trying to update 141 when
> the order of the test output changed, but found it would still fail
> occassionally because printf() and QMP events race with synchronous QMP
> communication.
> 
> I gave up and ported 141 to the existing Python API for QMP tests. The
> Python API is less affected by the order in which QEMU prints output
> because it does not print all QMP traffic by default.
> 
> The next commit changes the order in which QMP messages are received.
> Make 141 reliable first.
> 
> Cc: Hanna Czenczek <hreitz@redhat.com>
> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

> diff --git a/tests/qemu-iotests/141.out b/tests/qemu-iotests/141.out
> index 63203d9944..986f9f7598 100644
> --- a/tests/qemu-iotests/141.out
> +++ b/tests/qemu-iotests/141.out
> @@ -1,179 +1,69 @@
> -QA output created by 141
> -Formatting 'TEST_DIR/b.IMGFMT', fmt=IMGFMT size=1048576
> -Formatting 'TEST_DIR/m.IMGFMT', fmt=IMGFMT size=1048576 
> backing_file=TEST_DIR/b.IMGFMT backing_fmt=IMGFMT
> -Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=1048576 
> backing_file=TEST_DIR/m.IMGFMT backing_fmt=IMGFMT
> -{'execute': 'qmp_capabilities'}
> -{"return": {}}
> -
> +Creating bottom <- middle <- top backing file chain...
> +Starting VM...
>  === Testing drive-backup ===
> -
> -{'execute': 'blockdev-add',
> -          'arguments': {
> -              'node-name': 'drv0',
> -              'driver': 'IMGFMT',
> -              'file': {
> -                  'driver': 'file',
> -                  'filename': 'TEST_DIR/t.IMGFMT'
> -              }}}
> +{"execute": "blockdev-add", "arguments": {"driver": "qcow2", "file": 
> {"driver": "file", "filename": "TEST_DIR/PID-top"}, "node-name": "drv0"}}

This and other lines in the test output need image format filtering. You
have a literal "qcow2" in there, but the test case also runs (and fails
because of this) for qed.

Apart from this, the patch looks good to me.

Kevin