Re: [Qemu-devel] [PATCH 1/2] Acceptance tests: exclude "flaky" tests

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

On 6/21/19 8:09 AM, Cleber Rosa wrote:
> It's a fact that some tests may not be 100% reliable in all
> environments.  While it's a tough call to remove a useful test that
> from the tree because it may fail every 1/100th time (or so), having
> human attention drawn to known issues is very bad for humans and for
> the projects they manage.
> 
> As a compromise solution, this marks tests that are known to have
> issues, or that exercises known issues in QEMU or other components,
> and excludes them from the entry point.  As a consequence, tests
> marked as "flaky" will not be executed as part of "make
> check-acceptance".
> 
> Because such tests should be forgiven but never be forgotten, it's
> possible to list them with (assuming "make check-venv" or "make
> check-acceptance" has already initiatilized the venv):
> 
>   $ ./tests/venv/bin/avocado list -t flaky tests/acceptance
> 
> The current list of tests marked as flaky are a result of running
> the entire set of acceptance tests around 20 times.  The results
> were then processed with a helper script[1].  That either confirmed
> known issues (in the case of aarch64 and arm)[2] or revealed new
> ones (mips).
> 
> This also bumps the Avocado version to one that includes a fix to the
> parsing of multiple and mix "key:val" and simple tag values.
> 
> [1] https://raw.githubusercontent.com/avocado-framework/avocado/master/contrib/scripts/summarize-job-failures.py
> [2] https://bugs.launchpad.net/qemu/+bug/1829779
> 
> Signed-off-by: Cleber Rosa <crosa@redhat.com>
> ---
>  docs/devel/testing.rst                   | 17 +++++++++++++++++
>  tests/Makefile.include                   |  6 +++++-
>  tests/acceptance/boot_linux_console.py   |  2 ++
>  tests/acceptance/linux_ssh_mips_malta.py |  2 ++
>  tests/requirements.txt                   |  2 +-
>  5 files changed, 27 insertions(+), 2 deletions(-)
> 
> diff --git a/docs/devel/testing.rst b/docs/devel/testing.rst
> index da2d0fc964..ff4d8e2e1c 100644
> --- a/docs/devel/testing.rst
> +++ b/docs/devel/testing.rst
> @@ -574,6 +574,23 @@ may be invoked by running:
>  
>    tests/venv/bin/avocado run $OPTION1 $OPTION2 tests/acceptance/
>  
> +Tagging tests
> +-------------
> +
> +flaky
> +~~~~~
> +
> +If a test is known to fail intermittently, even if only every one
> +hundredth time, it's highly advisable to mark it as a flaky test.
> +This will prevent these individual tests from failing much larger
> +jobs, will avoid human interaction and time wasted to verify a known
> +issue, and worse of all, can lead to the discredit of automated
> +testing.
> +
> +To mark a test as flaky, add to its docstring.::
> +
> +  :avocado: tags=flaky

I certainly disagree with this patch, failing tests have to be fixed.
Why not tag all the codebase flaky and sing "happy coding"?

Anyway if this get accepted, 'flaky' tags must have the intermittent
failure well described, and a Launchpad/Bugzilla tracking ticket referenced.

> +
>  Manual Installation
>  -------------------
>  
> diff --git a/tests/Makefile.include b/tests/Makefile.include
> index db750dd6d0..4c97da2878 100644
> --- a/tests/Makefile.include
> +++ b/tests/Makefile.include
> @@ -1125,7 +1125,11 @@ TESTS_RESULTS_DIR=$(BUILD_DIR)/tests/results
>  # Any number of command separated loggers are accepted.  For more
>  # information please refer to "avocado --help".
>  AVOCADO_SHOW=app
> -AVOCADO_TAGS=$(patsubst %-softmmu,-t arch:%, $(filter %-softmmu,$(TARGET_DIRS)))
> +
> +# Additional tags that are added to each occurence of "--filter-by-tags"
> +AVOCADO_EXTRA_TAGS := ,-flaky
> +
> +AVOCADO_TAGS=$(patsubst %-softmmu,--filter-by-tags=arch:%$(AVOCADO_EXTRA_TAGS), $(filter %-softmmu,$(TARGET_DIRS)))
>  
>  ifneq ($(findstring v2,"v$(PYTHON_VERSION)"),v2)
>  $(TESTS_VENV_DIR): $(TESTS_VENV_REQ)
> diff --git a/tests/acceptance/boot_linux_console.py b/tests/acceptance/boot_linux_console.py
> index 32159503e9..6bd5c1ab53 100644
> --- a/tests/acceptance/boot_linux_console.py
> +++ b/tests/acceptance/boot_linux_console.py
> @@ -249,6 +249,7 @@ class BootLinuxConsole(Test):
>          """
>          :avocado: tags=arch:aarch64
>          :avocado: tags=machine:virt
> +        :avocado: tags=flaky
>          """
>          kernel_url = ('https://download.fedoraproject.org/pub/fedora/linux/'
>                        'releases/29/Everything/aarch64/os/images/pxeboot/vmlinuz')
> @@ -270,6 +271,7 @@ class BootLinuxConsole(Test):
>          """
>          :avocado: tags=arch:arm
>          :avocado: tags=machine:virt
> +        :avocado: tags=flaky
>          """
>          kernel_url = ('https://download.fedoraproject.org/pub/fedora/linux/'
>                        'releases/29/Everything/armhfp/os/images/pxeboot/vmlinuz')
> diff --git a/tests/acceptance/linux_ssh_mips_malta.py b/tests/acceptance/linux_ssh_mips_malta.py
> index aafb0c39f6..ae70b658e0 100644
> --- a/tests/acceptance/linux_ssh_mips_malta.py
> +++ b/tests/acceptance/linux_ssh_mips_malta.py
> @@ -208,6 +208,7 @@ class LinuxSSH(Test):
>          :avocado: tags=machine:malta
>          :avocado: tags=endian:big
>          :avocado: tags=device:pcnet32
> +        :avocado: tags=flaky
>          """
>          kernel_url = ('https://people.debian.org/~aurel32/qemu/mips/'
>                        'vmlinux-3.2.0-4-5kc-malta')
> @@ -222,6 +223,7 @@ class LinuxSSH(Test):
>          :avocado: tags=machine:malta
>          :avocado: tags=endian:little
>          :avocado: tags=device:pcnet32
> +        :avocado: tags=flaky
>          """
>          kernel_url = ('https://people.debian.org/~aurel32/qemu/mipsel/'
>                        'vmlinux-3.2.0-4-5kc-malta')
> diff --git a/tests/requirements.txt b/tests/requirements.txt
> index 3ae0e29ad7..58d63d171f 100644
> --- a/tests/requirements.txt
> +++ b/tests/requirements.txt
> @@ -1,5 +1,5 @@
>  # Add Python module requirements, one per line, to be installed
>  # in the tests/venv Python virtual environment. For more info,
>  # refer to: https://pip.pypa.io/en/stable/user_guide/#id1
> -avocado-framework==68.0
> +avocado-framework==69.1
>  paramiko
>