From f4a1b6536f70d33caa9da6c091b98038943998c9 Mon Sep 17 00:00:00 2001 From: Fam Zheng Date: Tue, 24 Jul 2018 16:47:38 +0800 Subject: [PATCH] docs: Describe using images in writing iotests Signed-off-by: Fam Zheng Reviewed-by: Eric Blake Reviewed-by: John Snow Signed-off-by: Kevin Wolf --- docs/devel/testing.rst | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/docs/devel/testing.rst b/docs/devel/testing.rst index 5e19cd50da..8e1fa3a66e 100644 --- a/docs/devel/testing.rst +++ b/docs/devel/testing.rst @@ -255,6 +255,17 @@ comparable library support for invoking and interacting with QEMU programs. If you opt for Python, it is strongly recommended to write Python 3 compatible code. +Both Python and Bash frameworks in iotests provide helpers to manage test +images. They can be used to create and clean up images under the test +directory. If no I/O or any protocol specific feature is needed, it is often +more convenient to use the pseudo block driver, ``null-co://``, as the test +image, which doesn't require image creation or cleaning up. Avoid system-wide +devices or files whenever possible, such as ``/dev/null`` or ``/dev/zero``. +Otherwise, image locking implications have to be considered. For example, +another application on the host may have locked the file, possibly leading to a +test failure. If using such devices are explicitly desired, consider adding +``locking=off`` option to disable image locking. + Docker based tests ================== -- 2.39.2