Re: [RFC PATCH] kunit: Support skipped tests

Alan Maguire
2020-05-13T10:08:03Z

On Tue, 12 May 2020, David Gow wrote:

> This is a proof-of-concept to support "skipping" tests.
>

Really glad to see skip support; nice work!

> The kunit_mark_skipped() macro marks the current test as "skipped", with
> the provided reason. The kunit_skip() macro will mark the test as
> skipped, and abort the test.
>
> The TAP specification supports this "SKIP directive" as a comment after
> the "ok" / "not ok" for a test. See the "Directives" section of the TAP
> spec for details:
> https://testanything.org/tap-specification.html#directives
>

My first thought before consulting this was the right answer is
to expand the kunit status from a bool to include skipped as
a possiblility (making it an "enum kunit_status") but the the,
above seems to classify skipping as a directive with a reason,
while the test status is still reported as "ok".

Despite that, I wonder if having test status as an enum still
might make sense? kunit_status_to_string() would still render
KUNIT_SKIPPED as "ok" in such a case, but having the skipped
state in status might make computing if the plan line should
print "skipped" easier (if all subtests have status == KUNIT_SKIPPED).
Taking that approach might also be more extensible; implementing
TODO and other directives would become much easier.

So instead of having a kunit_skip() macro, we could possibly
rework kunit_print_ok_not_ok() to be something like
kunit_print_status(), with a status enum value and an optional
directive string. That way, adding new status values would
be simply a case of adding to the enum and specifying
an associated string value ("ok" for skip, "not ok" for
TODO, etc). Plus a KUNIT_SKIPPED status could easily
progagate up from the tests to the plan result line
(all tests have status == SKIPPED => plan status = SKIPPED).

Would that work? Thanks!

Alan

> kunit_tool will parse this SKIP directive, and renders skipped tests in
> yellow and counts them. Skipped tests do not affect the result for a
> suite.
>
> Signed-off-by: David Gow <davidgow@google.com>
> ---
>
> Following on from discussions about the KCSAN test[1], which requires a
> multi-core/processor system to make sense, it would be useful for tests
> to be able to mark themselves as "skipped", where tests have runtime
> dependencies which aren't met.
>
> As a proof-of-concept, this patch doesn't implement some things which
> we'd ideally like to have (e.g., non-static "reasons" for skipping the
> test, maybe some SKIP macros akin to the EXPECT and ASSERT ones), and
> the implementation is still pretty hacky, but I though I'd put this out
> there to see if there are any thoughts on the concept in general.
>
> Cheers,
> -- David
>
> [1]: https://lkml.org/lkml/2020/5/5/31
>
> include/kunit/test.h | 12 ++++++++++++
> lib/kunit/kunit-example-test.c | 7 +++++++
> lib/kunit/test.c | 23 ++++++++++++++++-------
> tools/testing/kunit/kunit_parser.py | 21 +++++++++++++++++----
> 4 files changed, 52 insertions(+), 11 deletions(-)
>
> diff --git a/include/kunit/test.h b/include/kunit/test.h
> index 9b0c46a6ca1f..7817c5580b2c 100644
> --- a/include/kunit/test.h
> +++ b/include/kunit/test.h
> @@ -178,6 +178,7 @@ struct kunit_suite {
> /* private - internal use only */
> struct dentry *debugfs;
> char *log;
> + const char *skip_directive;
> };
>
> /**
> @@ -213,6 +214,8 @@ struct kunit {
> * protect it with some type of lock.
> */
> struct list_head resources; /* Protected by lock. */
> +
> + const char *skip_directive;
> };
>
> void kunit_init_test(struct kunit *test, const char *name, char *log);
> @@ -391,6 +394,15 @@ void kunit_cleanup(struct kunit *test);
>
> void kunit_log_append(char *log, const char *fmt, ...);
>
> +#define kunit_mark_skipped(test_or_suite, reason) \
> + (test_or_suite)->skip_directive = "SKIP " reason
> +
> +#define kunit_skip(test_or_suite, reason) \
> + do { \
> + kunit_mark_skipped(test_or_suite, reason); \
> + kunit_try_catch_throw(&((test_or_suite)->try_catch)); \
> + } while (0)
> +
> /*
> * printk and log to per-test or per-suite log buffer. Logging only done
> * if CONFIG_KUNIT_DEBUGFS is 'y'; if it is 'n', no log is allocated/used.
> diff --git a/lib/kunit/kunit-example-test.c b/lib/kunit/kunit-example-test.c
> index be1164ecc476..998401a61458 100644
> --- a/lib/kunit/kunit-example-test.c
> +++ b/lib/kunit/kunit-example-test.c
> @@ -29,6 +29,12 @@ static void example_simple_test(struct kunit *test)
> KUNIT_EXPECT_EQ(test, 1 + 1, 2);
> }
>
> +static void example_skip_test(struct kunit *test)
> +{
> + kunit_skip(test, "this test should be skipped");
> + KUNIT_EXPECT_EQ(test, 1 + 1, 2);
> +}
> +
> /*
> * This is run once before each test case, see the comment on
> * example_test_suite for more information.
> @@ -52,6 +58,7 @@ static struct kunit_case example_test_cases[] = {
> * test suite.
> */
> KUNIT_CASE(example_simple_test),
> + KUNIT_CASE(example_skip_test),
> {}
> };
>
> diff --git a/lib/kunit/test.c b/lib/kunit/test.c
> index ccb2ffad8dcf..84b9be3a8da7 100644
> --- a/lib/kunit/test.c
> +++ b/lib/kunit/test.c
> @@ -79,10 +79,12 @@ static void kunit_print_ok_not_ok(void *test_or_suite,
> bool is_test,
> bool is_ok,
> size_t test_number,
> - const char *description)
> + const char *description,
> + const char *directive)
> {
> struct kunit_suite *suite = is_test ? NULL : test_or_suite;
> struct kunit *test = is_test ? test_or_suite : NULL;
> + const char *directive_header = directive ? " # " : "";
>
> /*
> * We do not log the test suite results as doing so would
> @@ -93,13 +95,16 @@ static void kunit_print_ok_not_ok(void *test_or_suite,
> * representation.
> */
> if (suite)
> - pr_info("%s %zd - %s\n",
> + pr_info("%s %zd - %s%s%s\n",
> kunit_status_to_string(is_ok),
> - test_number, description);
> + test_number, description,
> + directive_header, directive ? directive : "");
> else
> - kunit_log(KERN_INFO, test, KUNIT_SUBTEST_INDENT "%s %zd - %s",
> + kunit_log(KERN_INFO, test,
> + KUNIT_SUBTEST_INDENT "%s %zd - %s%s%s",
> kunit_status_to_string(is_ok),
> - test_number, description);
> + test_number, description,
> + directive_header, directive ? directive : "");
> }
>
> bool kunit_suite_has_succeeded(struct kunit_suite *suite)
> @@ -122,7 +127,8 @@ static void kunit_print_subtest_end(struct kunit_suite *suite)
> kunit_print_ok_not_ok((void *)suite, false,
> kunit_suite_has_succeeded(suite),
> kunit_suite_counter++,
> - suite->name);
> + suite->name,
> + suite->skip_directive);
> }
>
> unsigned int kunit_test_case_num(struct kunit_suite *suite,
> @@ -232,6 +238,7 @@ void kunit_init_test(struct kunit *test, const char *name, char *log)
> if (test->log)
> test->log[0] = '\0';
> test->success = true;
> + test->skip_directive = NULL;
> }
> EXPORT_SYMBOL_GPL(kunit_init_test);
>
> @@ -357,7 +364,8 @@ static void kunit_run_case_catch_errors(struct kunit_suite *suite,
>
> kunit_print_ok_not_ok(&test, true, test_case->success,
> kunit_test_case_num(suite, test_case),
> - test_case->name);
> + test_case->name,
> + test.skip_directive);
> }
>
> int kunit_run_tests(struct kunit_suite *suite)
> @@ -378,6 +386,7 @@ EXPORT_SYMBOL_GPL(kunit_run_tests);
> static void kunit_init_suite(struct kunit_suite *suite)
> {
> kunit_debugfs_create_suite(suite);
> + suite->skip_directive = NULL;
> }
>
> int __kunit_test_suites_init(struct kunit_suite **suites)
> diff --git a/tools/testing/kunit/kunit_parser.py b/tools/testing/kunit/kunit_parser.py
> index 64aac9dcd431..ecfc8ee1da2f 100644
> --- a/tools/testing/kunit/kunit_parser.py
> +++ b/tools/testing/kunit/kunit_parser.py
> @@ -43,6 +43,7 @@ class TestCase(object):
> class TestStatus(Enum):
> SUCCESS = auto()
> FAILURE = auto()
> + SKIPPED = auto()
> TEST_CRASHED = auto()
> NO_TESTS = auto()
>
> @@ -107,6 +108,8 @@ def save_non_diagnositic(lines: List[str], test_case: TestCase) -> None:
>
> OkNotOkResult = namedtuple('OkNotOkResult', ['is_ok','description', 'text'])
>
> +OK_NOT_OK_SKIP = re.compile(r'^[\s]*(ok|not ok) [0-9]+ - (.*) # SKIP (.*)$')
> +
> OK_NOT_OK_SUBTEST = re.compile(r'^[\s]+(ok|not ok) [0-9]+ - (.*)$')
>
> OK_NOT_OK_MODULE = re.compile(r'^(ok|not ok) [0-9]+ - (.*)$')
> @@ -124,6 +127,10 @@ def parse_ok_not_ok_test_case(lines: List[str], test_case: TestCase) -> bool:
> if match:
> test_case.log.append(lines.pop(0))
> test_case.name = match.group(2)
> + skip_match = OK_NOT_OK_SKIP.match(line)
> + if skip_match:
> + test_case.status = TestStatus.SKIPPED
> + return True
> if test_case.status == TestStatus.TEST_CRASHED:
> return True
> if match.group(1) == 'ok':
> @@ -190,9 +197,9 @@ def max_status(left: TestStatus, right: TestStatus) -> TestStatus:
> return TestStatus.TEST_CRASHED
> elif left == TestStatus.FAILURE or right == TestStatus.FAILURE:
> return TestStatus.FAILURE
> - elif left != TestStatus.SUCCESS:
> + elif left != TestStatus.SUCCESS and left != TestStatus.SKIPPED:
> return left
> - elif right != TestStatus.SUCCESS:
> + elif right != TestStatus.SUCCESS and right != TestStatus.SKIPPED:
> return right
> else:
> return TestStatus.SUCCESS
> @@ -281,10 +288,13 @@ def parse_run_tests(kernel_output) -> TestResult:
> total_tests = 0
> failed_tests = 0
> crashed_tests = 0
> + skipped_tests = 0
> test_result = parse_test_result(list(isolate_kunit_output(kernel_output)))
> for test_suite in test_result.suites:
> if test_suite.status == TestStatus.SUCCESS:
> print_suite_divider(green('[PASSED] ') + test_suite.name)
> + elif test_suite.status == TestStatus.SKIPPED:
> + print_suite_divider(yellow('[SKIPPED] ') + test_suite.name)
> elif test_suite.status == TestStatus.TEST_CRASHED:
> print_suite_divider(red('[CRASHED] ' + test_suite.name))
> else:
> @@ -293,6 +303,9 @@ def parse_run_tests(kernel_output) -> TestResult:
> total_tests += 1
> if test_case.status == TestStatus.SUCCESS:
> print_with_timestamp(green('[PASSED] ') + test_case.name)
> + elif test_case.status == TestStatus.SKIPPED:
> + skipped_tests += 1
> + print_with_timestamp(yellow('[SKIPPED] ') + test_case.name)
> elif test_case.status == TestStatus.TEST_CRASHED:
> crashed_tests += 1
> print_with_timestamp(red('[CRASHED] ' + test_case.name))
> @@ -306,6 +319,6 @@ def parse_run_tests(kernel_output) -> TestResult:
> print_with_timestamp(DIVIDER)
> fmt = green if test_result.status == TestStatus.SUCCESS else red
> print_with_timestamp(
> - fmt('Testing complete. %d tests run. %d failed. %d crashed.' %
> - (total_tests, failed_tests, crashed_tests)))
> + fmt('Testing complete. %d tests run. %d failed. %d crashed. %d skipped.' %
> + (total_tests, failed_tests, crashed_tests, skipped_tests)))
> return test_result
> --
> 2.26.2.645.ge9eca65c58-goog
>
>