On Tue, Aug 2, 2022 at 9:12 AM Maíra Canal <mairacanal@xxxxxxxxxx> wrote: > > Currently, in order to compare arrays 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_ARREQ and > KUNIT_EXPECT_ARRNEQ 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 arrays. I totally agree with this. The only reason I hadn't sent an RFC out for this so far is * we didn't have enough use cases quite yet (now resolved) * I wasn't sure how we'd want to format the failure message. For the latter, right now this series produces dst == 00000000: 33 0a 60 12 00 a8 00 00 00 00 8e 6b 33 0a 60 12 00000010: 00 00 00 00 00 a8 8e 6b 33 0a 00 00 00 00 result->expected == 00000000: 31 0a 60 12 00 a8 00 00 00 00 81 6b 33 0a 60 12 00000010: 00 00 00 00 01 a8 8e 6b 33 0a 00 00 00 00 I was thinking something like what KASAN produces would be nice, e.g. from https://www.kernel.org/doc/html/v5.19/dev-tools/kasan.html#error-reports (I'll paste the bit here, but my email client doesn't support monospaced fonts, so it won't look nice on my end) Memory state around the buggy address: ffff8801f44ec200: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb ffff8801f44ec280: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc >ffff8801f44ec300: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 03 ^ I just wasn't quite sure how to do it for a diff, since this only really works well when showing one bad byte. If we blindly followed that approach, we get dst == >00000000: 33 0a 60 12 00 a8 00 00 00 00 8e 6b 33 0a 60 12 ^ >00000010: 00 00 00 00 00 a8 8e 6b 33 0a 00 00 00 00 ^ result->expected == >00000000: 31 0a 60 12 00 a8 00 00 00 00 81 6b 33 0a 60 12 ^ >00000010: 00 00 00 00 01 a8 8e 6b 33 0a 00 00 00 00 ^ But perhaps we could instead highlight the bad bytes with something like dst == 00000000: 33 0a 60 12 00 a8 00 00 00 00 <8e> 6b 33 0a 60 12 00000010: 00 00 00 00 <00> a8 8e 6b 33 0a 00 00 00 00 result->expected == 00000000: 31 0a 60 12 00 a8 00 00 00 00 <81> 6b 33 0a 60 12 00000010: 00 00 00 00 <01> a8 8e 6b 33 0a 00 00 00 00 Thoughts, suggestions?
