On Sat, 10 Jun 2023 at 08:52, Rae Moar rmoar@google.com wrote:
Hello everyone,
This is an RFC patch series to propose the addition of a test attributes framework to KUnit.
There has been interest in filtering out "slow" KUnit tests. Most notably, a new config, CONFIG_MEMCPY_SLOW_KUNIT_TEST, has been added to exclude particularly slow memcpy tests (https://lore.kernel.org/all/20230118200653.give.574-kees@kernel.org/).
Awesome: this is a long overdue feature.
This proposed attributes framework would be used to save and access test associated data, including whether a test is slow. These attributes would be reportable (via KTAP and command line output) and some will be filterable.
Why wouldn't they all be filterable? I guess I can imagine some where filtering wouldn't be useful, but I can't think of a technical reason why the filter shouldn't work.
Also, as I understand it, I think this could also work with data which is not "saved" in this kunit_attributes struct you define. So we could have attributes which are generated automatically from other information about the test. I could definitely see value in being able to filter on things like "is_parameterised" or "runs_at_init" or similar.
Finally, it'd be really great if these attributes could apply to individual parameters in parameterised tests, in which case we could have and filter on the parameter value. That seems like it could be incredibly useful.
This framework is designed to allow for the addition of other attributes in the future. These attributes could include whether the test is flaky, associated test files, etc.
A small part of me is hesitant to add this much framework code for only one attribute, so it'd be nice to look into at least having an RFC for some of these. Hopefully we don't actually have flaky tests, but "is_deterministic" would be nice (alongside a future ability to inject a random seed, or similar). Other properties like "is_threadsafe", "is_reentrant", etc could be useful for future features. And I'm sure there could be some more subsystem-specific things which would be useful to filter on, too.
Some of these could probably replace the need for custom code to make the test skip itself if dependencies aren't met, too, which would be fun.
I'm not sure "associated test files" quite gels perfectly with this system as-is (assuming I understand what that refers to). If it's the ability to "attach" extra data (logs, etc) to the KTAP output, that's possibly best injected at runtime, or added by the separate parser, rather than hardcoded in the kernel.
Note that this could intersect with the discussions on how to format test-associated data in KTAP v2 that I am also involved in (https://lore.kernel.org/all/20230420205734.1288498-1-rmoar@google.com/).
I definitely need to re-read and respond to that. I'm not 100% thrilled with the output format here, and I think the goal with KTAP "test associated data" is, as you say, related, but not identical to this. There'd definitely be data which doesn't make sense as a KUnit attribute which we might want to add to the output (e.g., data only calcuated while the test runs), and attributes which we might not want to always print out with the results.
If the overall idea seems good, I'll make sure to add tests/documentation, and more patches marking existing tests as slow to the patch series.
I think the series is good overall. If no-one else objects, let's move forward with it. I'd definitely prefer to see a few more tests and some documentation. Having another attribute would be great, too, though I can certainly live with that being a separate series.
Thanks! Rae
Rae Moar (6): kunit: Add test attributes API structure kunit: Add speed attribute kunit: Add ability to filter attributes kunit: tool: Add command line interface to filter and report attributes kunit: memcpy: Mark tests as slow using test attributes kunit: time: Mark test as slow using test attributes
include/kunit/attributes.h | 41 ++++ include/kunit/test.h | 62 ++++++ kernel/time/time_test.c | 2 +- lib/kunit/Makefile | 3 +- lib/kunit/attributes.c | 280 +++++++++++++++++++++++++ lib/kunit/executor.c | 89 ++++++-- lib/kunit/executor_test.c | 8 +- lib/kunit/kunit-example-test.c | 9 + lib/kunit/test.c | 17 +- lib/memcpy_kunit.c | 8 +- tools/testing/kunit/kunit.py | 34 ++- tools/testing/kunit/kunit_kernel.py | 6 +- tools/testing/kunit/kunit_tool_test.py | 41 ++-- 13 files changed, 536 insertions(+), 64 deletions(-) create mode 100644 include/kunit/attributes.h create mode 100644 lib/kunit/attributes.c
base-commit: fefdb43943c1a0d87e1b43ae4d03e5f9a1d058f4
2.41.0.162.gfafddb0af9-goog