Re: [PATCH v2 6/8] iotests: always use a unique sub-directory per test

[Eric Blake]

On Fri, Mar 03, 2023 at 04:07:25PM +0000, Daniel P. Berrangé wrote:
> The current test runner is only safe against parallel execution within
> a single instance of the 'check' process, and only if -j is given a
> value greater than 2. This prevents running multiple copies of the
> 'check' process for different test scenarios.
> 
> This change switches the output / socket directories to always include
> the test name, image format and image protocol. This should allow full
> parallelism of all distinct test scenarios. eg running both qcow2 and
> raw tests at the same time, or both file and nbd tests at the same
> time.
> 
> It would be possible to allow for parallelism of the same test scenario
> by including the pid, but that would potentially let many directories
> accumulate over time on failures, so is not done.
> 
> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
> ---
>  tests/qemu-iotests/testrunner.py | 20 ++++++++++----------
>  1 file changed, 10 insertions(+), 10 deletions(-)

git bisect points to this commit as being the reason behind the
following regression in iotests:

$ ./check -nbd 104
...
--- /home/eblake/qemu/tests/qemu-iotests/104.out
+++ /home/eblake/qemu/build/tests/qemu-iotests/scratch/raw-nbd-104/104.out.bad
@@ -2,11 +2,11 @@
 === Check qemu-img info output ===

 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=1024
-image: TEST_DIR/t.IMGFMT
+image: nbd+unix://?socket=/tmp/tmpqathrkpn/IMGFMT-nbd-104/nbd
 file format: IMGFMT
 virtual size: 1 KiB (1024 bytes)
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=1234
-image: TEST_DIR/t.IMGFMT
+image: nbd+unix://?socket=/tmp/tmpqathrkpn/IMGFMT-nbd-104/nbd
 file format: IMGFMT
 virtual size: 1.5 KiB (1536 bytes)
 *** done
Failures: 104

Back in 2015, commit a231cb2726, we added a hack that turned
nbd://... into TEST_DIR/t.IMGFMT to satisfy the output matching in the
various iotests, but with our new per-test directories, that filter is
no longer firing.

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org