unit/zap: add MT_MATCH_CASE mixed-case test

[chrislongros]

Motivation and Context

Adds MT_MATCH_CASE coverage for MT_NORMALIZE lookups that miss from #18654

Description

Adds test_norm_match_case, run against a normalizing microzap and fatzap.

• MT_NORMALIZE: a differently-cased name matches.
• MT_NORMALIZE | MT_MATCH_CASE: only the stored casing matches; differently-cased name does not.

How Has This Been Tested?

Built tests/unit/test_zap and ran the suite:

>  make unit T=zap TOPT='zap.norm_match_case'
  UNITTEST tests/unit/test_zap
Running test suite with seed 0x071ebff6...
zap.norm_match_case
  type=micro                         [ OK    ] [ 0.00002834 / 0.00002752 CPU ]
  type=fat                           [ OK    ] [ 0.00003386 / 0.00003302 CPU ]
2 of 2 (100%) tests successful, 0 (0%) test skipped.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Performance enhancement (non-breaking change which improves efficiency)
• Code cleanup (non-breaking change which makes code smaller or more readable)
• Quality assurance (non-breaking change which makes the code more robust against bugs)
• Documentation (a change to man pages or other documentation)

Checklist:

• My code follows the OpenZFS code style requirements.
• I have updated the documentation accordingly.
• I have read the contributing document.
• All commit messages are properly formatted and contain Signed-off-by.

[robn]

These are my tests for zap_lookup_norm/zap_remove_norm: robn/zap-unit-casenorm. They also exercise the Unicode normalization forms and the conflict API. I was actually going to post the PR for these today, but this one turned up over the weekend :)

(Incidentally, this was the reason I started putting all this test stuff together - I started looking at #7633 and traced it into the ZAP guts, and had no confidence about changing anything without breaking something else).

@chrislongros similar question to #18639 - do you want to go first and I'll follow, or combine them, or something else?

[chrislongros]

These are my tests for zap_lookup_norm/zap_remove_norm: robn/zap-unit-casenorm. They also exercise the Unicode normalization forms and the conflict API. I was actually going to post the PR for these today, but this one turned up over the weekend :)

(Incidentally, this was the reason I started putting all this test stuff together - I started looking at #7633 and traced it into the ZAP guts, and had no confidence about changing anything without breaking something else).

@chrislongros similar question to #18639 - do you want to go first and I'll follow, or combine them, or something else?

The mock functions you introduce are the right direction! Go ahead and I'll follow.

[robn]

@chrislongros thank you! #18654 posted.

[behlendorf]

@chrislongros the path is clear!

[robn]

This looks great, thanks.

Turns out that U8_TEXTPREP_TOUPPER is actually valid for the Unicode normalization forms too, and MT_MATCH_CASE also defangs that. I don't think its worth adding that here unless you especially wanted to; it's already kind of unclear what any of this means for ZFS proper (vs u8_textprep itself). I'll be down that way soon, I think.

[behlendorf]

Looks good. Sorry about the delay in taking another look at this.