On Wed, Sep 29, 2021 at 7:27 PM David Gow davidgow@google.com wrote:
On Thu, Sep 30, 2021 at 3:54 AM Daniel Latypov dlatypov@google.com wrote:
The new --run_isolated flag makes the tool boot the kernel once per suite or test, preventing leftover state from one suite to impact the other. This can be useful as a starting point to debugging test hermeticity issues.
Note: it takes a lot longer, so people should not use it normally.
Consider the following very simplified example:
bool disable_something_for_test = false; void function_being_tested() { ... if (disable_something_for_test) return; ... }
static void test_before(struct kunit *test) { disable_something_for_test = true; function_being_tested(); /* oops, we forgot to reset it back to false */ }
static void test_after(struct kunit *test) { /* oops, now "fixing" test_before can cause test_after to fail! */ function_being_tested(); }
Presented like this, the issues are obvious, but it gets a lot more complicated to track down as the amount of test setup and helper functions increases.
Another use case is memory corruption. It might not be surfaced as a failure/crash in the test case or suite that caused it. I've noticed in kunit's own unit tests, the 3rd suite after might be the one to finally crash after an out-of-bounds write, for example.
Example usage:
Per suite: $ ./tools/testing/kunit/kunit.py run --kunitconfig=lib/kunit --run_isolated=suite ... Starting KUnit Kernel (1/7)... ============================================================ ======== [PASSED] kunit_executor_test ======== .... Testing complete. 5 tests run. 0 failed. 0 crashed. 0 skipped. Starting KUnit Kernel (2/7)... ============================================================ ======== [PASSED] kunit-try-catch-test ======== ...
Per test: $ ./tools/testing/kunit/kunit.py run --kunitconfig=lib/kunit --run_isolated=test Starting KUnit Kernel (1/23)... ============================================================ ======== [PASSED] kunit_executor_test ======== [PASSED] parse_filter_test ============================================================ Testing complete. 1 tests run. 0 failed. 0 crashed. 0 skipped. Starting KUnit Kernel (2/23)... ============================================================ ======== [PASSED] kunit_executor_test ======== [PASSED] filter_subsuite_test ...
It works with filters as well: $ ./tools/testing/kunit/kunit.py run --kunitconfig=lib/kunit --run_isolated=suite example ... Starting KUnit Kernel (1/1)... ============================================================ ======== [PASSED] example ======== ...
It also handles test filters, '*.*skip*' runs these 3 tests: kunit_status.kunit_status_mark_skipped_test example.example_skip_test example.example_mark_skipped_test
Signed-off-by: Daniel Latypov dlatypov@google.com Reviewed-by: David Gow davidgow@google.com
Thanks. This is good. A part of me still would've preferred the TAP header to have been altered, but it probably makes more sense to leave that until after Rae's parser rework patch anyway, which has better support for multiple possible TAP headers anyway.
I did find an issue when running this under qemu/i386: a timing problem with interleaved lines. We could do something drastic, like having a marker at the start of every line to identify which ones are tests, but that does seem like overkill for a (hopefully) rare problem. Just ignoring obviously invalid lines should do it. Futher details below.
-- David
tools/testing/kunit/kunit.py | 95 ++++++++++++++++++++------ tools/testing/kunit/kunit_tool_test.py | 40 +++++++++++ 2 files changed, 114 insertions(+), 21 deletions(-)
diff --git a/tools/testing/kunit/kunit.py b/tools/testing/kunit/kunit.py index 5e717594df5b..b9d63f558765 100755 --- a/tools/testing/kunit/kunit.py +++ b/tools/testing/kunit/kunit.py @@ -16,7 +16,7 @@ assert sys.version_info >= (3, 7), "Python version is too old"
from collections import namedtuple from enum import Enum, auto -from typing import Iterable +from typing import Iterable, List
import kunit_config import kunit_json @@ -31,13 +31,13 @@ KunitBuildRequest = namedtuple('KunitBuildRequest', ['jobs', 'build_dir', 'alltests', 'make_options']) KunitExecRequest = namedtuple('KunitExecRequest',
['timeout', 'build_dir', 'alltests','filter_glob', 'kernel_args'])
['timeout', 'build_dir', 'alltests','filter_glob', 'kernel_args', 'run_isolated'])KunitParseRequest = namedtuple('KunitParseRequest', ['raw_output', 'build_dir', 'json']) KunitRequest = namedtuple('KunitRequest', ['raw_output','timeout', 'jobs', 'build_dir', 'alltests', 'filter_glob',
'kernel_args', 'json', 'make_options'])
'kernel_args', 'run_isolated', 'json', 'make_options'])KernelDirectoryPath = sys.argv[0].split('tools/testing/kunit/')[0]
@@ -91,23 +91,68 @@ def build_tests(linux: kunit_kernel.LinuxSourceTree, 'built kernel successfully', build_end - build_start)
+def _list_tests(linux: kunit_kernel.LinuxSourceTree, request: KunitExecRequest) -> List[str]:
args = ['kunit.action=list']if request.kernel_args:args.extend(request.kernel_args)output = linux.run_kernel(args=args,timeout=None if request.alltests else request.timeout,filter_glob=request.filter_glob,build_dir=request.build_dir)lines = kunit_parser.extract_tap_lines(output)# Hack! Drop the dummy TAP version header that the executor prints out.lines.pop()return list(lines)+def _suites_from_test_list(tests: List[str]) -> List[str]:
"""Extracts all the suites from an ordered list of tests."""suites = [] # type: List[str]for t in tests:parts = t.split('.', maxsplit=2)if len(parts) != 2:raise ValueError(f'internal KUnit error, test name should be of the form "<suite>.<test>", got "{t}"')It turns out that this can trigger on some machines/architectures if there are other lines of kernel output which either get interspersed in the test list, or -- more likely -- between the test list and the "Restarting System" line.
On i386, under qemu, I'm seeing this output: $ qemu-system-x86_64 -nodefaults -m 1024 -kernel .kunit/arch/x86/boot/bzImage -append 'kunit.action=list mem=1G console=tty kunit_shutdown=halt console=ttyS0 kunit_shutdown=reboot' -no-reboot -nographic -serial stdio ... property-entry.pe_test_reference random: fast init done input: ImExPS/2 Generic Explorer Mouse as /devices/platform/i8042/serio1/input/input2 reboot: Restarting system reboot: machine restart
Which translates into the following kunit_tool error: $ ./tools/testing/kunit/kunit.py run --run_isolated=suite --arch=i386 ... File "./tools/testing/kunit/kunit.py", line 114, in _suites_from_test_list raise ValueError(f'internal KUnit error, test name should be of the form "<suite>.<test>", got "{t}"') ValueError: internal KUnit error, test name should be of the form "<suite>.<test>", got "random: fast init done"
Could we maybe ignore entries of the incorrect form?
I'm thinking we change _list_tests() above like - return list(lines) + + # Filter out any extraneous non-test output that might have gotten mixed in. + return [l for l in lines if re.match('^\w+.\w+$', l)]
The problem with \w is that it doesn't match -. So I'm thinking we maybe go with something very lax like '^[^\s.]+.[^\s.]+$'
Since we don't have any requirements on the naming convention, I don't know if we can be stricter. Like, KUNIT_CASE() sorta enforces that test cases follow C identifier naming rules, but users could always work around it fairly easily by instantiating the struct directly.