test: carry validateFunc in every table

[retr0h]

An audit against CONTRIBUTING.md, matching the
ones done in nats-client#152
and nats-server#118. Test
files only; no production code changes.

What was wrong

CONTRIBUTING says external test tables carry validateFunc callbacks. Eight of
the fourteen public test files had none at all, and four more mixed the two
styles: a validateFunc for the success path while the loop still branched on
an expectation field for the error path.

Across the repository, 165 tables named that expectation eleven different ways —
expected, expectErr, expectRan, expectStatus, want, wantErr,
wantNil, wantLen, wantStatus, wantCapture, contains.

The mixed form also made the callback optional:

if tc.validateFunc != nil {
    tc.validateFunc(cmd)
}

TestDecode's case "Decodes nil data without error" supplied no callback, so
it checked only that Decode returned no error and never looked at the value it
decoded. Making the callback mandatory is what surfaced it. It now states what
it expects.

Two loops also decided things the case should own:
TestRunTaskStoresResultForAllPaths and TestHostResults computed a value and
asserted on it before handing what was left to the callback.

What changed

• All 165 tables carry a mandatory validateFunc. None is optional.
• The loop no longer decides anything: it makes the call and hands the results
  over. Error and success rows are the same shape.
• The assertions inside the callbacks are the ones that were already in the loop
  bodies, moved to the case that owns them. The one exception is the case above,
  which gained an assertion it did not have.
• ops_public_test.go (101 tables) and step_public_test.go (14) were uniform
  and converted mechanically; runner_public_test.go needed each of its seven
  tables done individually.
• Selector columns that are genuine inputs, such as checkTask and
  lookupName, are kept — they say which thing to look at, not what to expect.

Verification

just go-vet reports 0 issues, just test passes, and coverage holds at exactly
100.0%.

Related

The same sentence was missing from OSAPI's CONTRIBUTING even though it is the
heaviest user of the convention; added in
osapi#484. gohai neither documents
nor follows it and is tracked separately.

🤖 Generated with Claude Code

https://claude.ai/code/session_01CM5qrNtYQvdKcemkS5YpiP

[github-actions]

Thank you for contributing to this project! 😊🕹️

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

@@            Coverage Diff            @@
##              main      #100   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           14        14           
  Lines         2866      2866           
=========================================
  Hits          2866      2866           

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