Re: [PATCH v3 0/3] Introduce KUNIT_EXPECT_MEMEQ and KUNIT_EXPECT_MEMNEQ macros

["Maíra Canal" <mairacanal@riseup.net>]

On 8/5/22 01:44, David Gow wrote:
> On Thu, Aug 4, 2022 at 5:59 AM Maíra Canal <mairacanal@riseup.net> wrote:
>>
>> Currently, in order to compare memory blocks in KUnit, the KUNIT_EXPECT_EQ or
>> KUNIT_EXPECT_FALSE macros are used in conjunction with the memcmp function,
>> such as:
>>   KUNIT_EXPECT_EQ(test, memcmp(foo, bar, size), 0);
>>
>> Although this usage produces correct results for the test cases, if the
>> expectation fails the error message is not very helpful, indicating only the
>> return of the memcmp function.
>>
>> Therefore, create a new set of macros KUNIT_EXPECT_MEMEQ and
>> KUNIT_EXPECT_MEMNEQ that compare memory blocks until a determined size. In
>> case of expectation failure, those macros print the hex dump of the memory
>> blocks, making it easier to debug test failures for memory blocks.
>>
>> Other than the style changes, this v3 brings alignment to the bytes, making
>> it easier to identify the faulty bytes. So, on the previous version, the
>> output from a failure would be:
>> [14:27:42] # xrgb8888_to_rgb565_test: EXPECTATION FAILED at drivers/gpu/drm/tests/drm_format_helper_test.c:248
>> [14:27:42] Expected dst == result->expected, but
>> [14:27:42] dst ==
>> [14:27:42] 33 0a <60> 12 00 a8 00 00 <00> 00 8e 6b <33> 0a 60 12
>> [14:27:42] 00 00 <00> 00 00 a8 <8e> 6b 33 0a 00 00 <00> 00
>> [14:27:42] result->expected ==
>> [14:27:42] 33 0a <61> 12 00 a8 00 00 <01> 00 8e 6b <31> 0a 60 12
>> [14:27:42] 00 00 <01> 00 00 a8 <81> 6b 33 0a 00 00 <01> 00
>>
>> Now, with the alignment, the output is:
>> [14:27:42] # xrgb8888_to_rgb565_test: EXPECTATION FAILED at drivers/gpu/drm/tests/drm_format_helper_test.c:248
>> [14:27:42] Expected dst == result->expected, but
>> [14:27:42] dst ==
>> [14:27:42] 33  0a <60> 12  00  a8  00  00 <00> 00  8e  6b <33> 0a  60  12
>> [14:27:42] 00  00 <00> 00  00  a8 <8e> 6b  33  0a  00  00 <00> 00
>> [14:27:42] result->expected ==
>> [14:27:42] 33  0a <61> 12  00  a8  00  00 <01> 00  8e  6b <31> 0a  60  12
>> [14:27:42] 00  00 <01> 00  00  a8 <81> 6b  33  0a  00  00 <01> 00
>>
>> Moreover, on the raw output, there were some indentation problems. Those
>> problems were solved with the use of KUNIT_SUBSUBTEST_INDENT.
>>
>> The first patch of the series introduces the KUNIT_EXPECT_MEMEQ and
>> KUNIT_EXPECT_MEMNEQ. The second patch adds an example of memory block
>> expectations on the kunit-example-test.c. And the last patch replaces the
>> KUNIT_EXPECT_EQ for KUNIT_EXPECT_MEMEQ on the existing occurrences.
>>
>> Best Regards,
>> - Maíra Canal
>>
>> v1 -> v2: https://lore.kernel.org/linux-kselftest/2a0dcd75-5461-5266-2749-808f638f4c50@riseup.net/T/#m402cc72eb01fb3b88d6706cf7d1705fdd51e5da2
>>
>> - Change "determinated" to "specified" (Daniel Latypov).
>> - Change the macro KUNIT_EXPECT_ARREQ to KUNIT_EXPECT_MEMEQ, in order to make
>> it easier for users to infer the right size unit (Daniel Latypov).
>> - Mark the different bytes on the failure message with a <> (Daniel Latypov).
>> - Replace a constant number of array elements for ARRAY_SIZE() (André Almeida).
>> - Rename "array" and "expected" variables to "array1" and "array2" (Daniel Latypov).
>>
>> v2 -> v3: https://lore.kernel.org/linux-kselftest/20220802212621.420840-1-mairacanal@riseup.net/T/#t
>>
>> - Make the bytes aligned at output.
>> - Add KUNIT_SUBSUBTEST_INDENT to the output for the indentation (Daniel Latypov).
>> - Line up the trailing \ at macros using tabs (Daniel Latypov).
>> - Line up the params to the functions (Daniel Latypov).
>> - Change "Increament" to "Augment" (Daniel Latypov).
>> - Use sizeof() for array sizes (Daniel Latypov).
>>
>> Maíra Canal (3):
>>   kunit: Introduce KUNIT_EXPECT_MEMEQ and KUNIT_EXPECT_MEMNEQ macros
>>   kunit: Add KUnit memory block assertions to the example_all_expect_macros_test
>>   kunit: Use KUNIT_EXPECT_MEMEQ macro
>>
>>  .../gpu/drm/tests/drm_format_helper_test.c    |  6 +-
>>  include/kunit/assert.h                        | 34 +++++++++
>>  include/kunit/test.h                          | 76 +++++++++++++++++++
>>  lib/kunit/assert.c                            | 56 ++++++++++++++
>>  lib/kunit/kunit-example-test.c                |  7 ++
>>  net/core/dev_addr_lists_test.c                |  4 +-
>>  6 files changed, 178 insertions(+), 5 deletions(-)
>>
>> --
>> 2.37.1
>>
>> --
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> 
> These patches look pretty good to me overall, but I was unable to
> apply v3 to test -- it looks like the mail client has wrapped some
> lines or something...
> 
> davidgow@slicestar:~/linux-kselftest$ git am
> ./v3_20220803_mairacanal_introduce_kunit_expect_memeq_and_kunit_expect_memneq_macros.mbx
> Applying: kunit: Introduce KUNIT_EXPECT_MEMEQ and KUNIT_EXPECT_MEMNEQ macros
> error: corrupt patch at line 24
> Patch failed at 0001 kunit: Introduce KUNIT_EXPECT_MEMEQ and
> KUNIT_EXPECT_MEMNEQ macros
> 
> Checkpatch also picks up an issue:
> ERROR: patch seems to be corrupt (line wrapped?)
> #62: FILE: include/kunit/assert.h:255:
>                                    const struct va_format *message,
> 
> v2 applied clearnly, so it seems to be specific to v3.

I'll check this issue and submit a v4. Thank you!

> 
> In general, I like the patches, though. While I think there are a few
> places it'd be slightly suboptimale if it's being used to compare more
> structured data, such as the prospect of comparing padding between
> elements, as well as the output formatting not being ideal. It's
> perfect for the cases where memcmp() otherwise would be used, though.

Do you any take on how to make the output formatting more ideal?

Best Regards,
- Maíra Canal

> 
> Cheers,
> -- David