[Linux-kernel-mentees] [PATCH] lib: kunit: add test_min_heap test conversion to KUnit

[Vitor Massaru Iha]

Hi Peter,

On Wed, Jul 29, 2020 at 5:39 PM <peterz at infradead.org> wrote:
>
> On Wed, Jul 29, 2020 at 05:11:46PM -0300, Vitor Massaru Iha wrote:
> > This adds the conversion of the runtime tests of test_min_heap,
> > from `lib/test_min_heap.c` to KUnit tests.
> >
> > Please apply this commit first (linux-kselftest/kunit-fixes):
> > 3f37d14b8a3152441f36b6bc74000996679f0998 kunit: kunit_config: Fix parsing of CONFIG options with space
> >
> > Signed-off-by: Vitor Massaru Iha <vitor at massaru.org>
> > ---
> >  lib/Kconfig.debug                         |  29 ++++--
> >  lib/Makefile                              |   2 +-
> >  lib/{test_min_heap.c => min_heap_kunit.c} | 117 ++++++++++++----------
> >  3 files changed, 83 insertions(+), 65 deletions(-)
> >  rename lib/{test_min_heap.c => min_heap_kunit.c} (60%)
>
> So where's the win? What's KUnit, why should I care and more lines.

KUnit is a unit testing and mocking framework for the Linux kernel. [0]

In Kconfig.debug you only have some more information about KUnit.

If the number of lines is a parameter that should be considered, I can
change sections like this

-                       if (last > values[0]) {
-                               pr_err("error: expected %d <= %d\n", last,
-                                       values[0]);
-                               err++;
-                       }
+                       KUNIT_EXPECT_FALSE_MSG(context,
+                                              last > values[0],
+                                              "expected %d <= %d\n",
+                                              last, values[0]);

To this:

-                       if (last > values[0]) {
-                               pr_err("error: expected %d <= %d\n", last,
-                                       values[0]);
-                               err++;
-                       }
+                       KUNIT_EXPECT_FALSE_MSG(context, last >
values[0],  "expected %d <= %d\n",  last, values[0]);

And from this:

+static struct kunit_case __refdata min_heap_test_cases[] = {
+       KUNIT_CASE(test_heapify_all_true),
+       KUNIT_CASE(test_heapify_all_false),
+       KUNIT_CASE(test_heap_push_true),
+       KUNIT_CASE(test_heap_push_false),
+       KUNIT_CASE(test_heap_pop_push_true),
+       KUNIT_CASE(test_heap_pop_push_false),
+       {}

To this:

+static struct kunit_case __refdata min_heap_test_cases[] = {
+       KUNIT_CASE(test_min_heap),
+       {}

I did the latter this way to be more informative, but if the goal is
to reduce lines of code, this is possible.

The results can be seen this way:

This is an excerpt from the test.log with the result in TAP format:
[snip]
ok 5 - example
    # Subtest: min-heap
    1..6
    ok 1 - test_heapify_all_true
    ok 2 - test_heapify_all_false
    ok 3 - test_heap_push_true
    ok 4 - test_heap_push_false
    ok 5 - test_heap_pop_push_true
    ok 6 - test_heap_pop_push_false
[snip]

And this from kunit-tool:
[snip]
[18:43:32] ============================================================
[18:43:32] ======== [PASSED] min-heap ========
[18:43:32] [PASSED] test_heapify_all_true
[18:43:32] [PASSED] test_heapify_all_false
[18:43:32] [PASSED] test_heap_push_true
[18:43:32] [PASSED] test_heap_push_false
[18:43:32] [PASSED] test_heap_pop_push_true
[18:43:32] [PASSED] test_heap_pop_push_false
[18:43:32] ============================================================
[18:43:32] Testing complete. 20 tests run. 0 failed. 0 crashed.
[18:43:32] Elapsed time: 9.758s total, 0.001s configuring, 6.012s
building, 0.000s running
[snip]

BR,
Vitor

[0] https://www.kernel.org/doc/html/latest/dev-tools/kunit/index.html#what-is-kunit