test: migrate stats/base/dists/weibull/logpdf to ULP-based assertions

[Planeshifter]

Resolves a part of #11352.

Description

What is the purpose of this pull request?

This pull request:

• migrates the tests for stats/base/dists/weibull/logpdf from computed relative-tolerance comparisons (delta = abs( y - expected[ i ] ) / tol = N * EPS * abs( expected[ i ] ), asserted via t.ok( delta <= tol, ... )) to ULP-difference assertions using @stdlib/assert/is-almost-same-value.
• applies the migration to test/test.logpdf.js, test/test.factory.js, and test/test.native.js (test/test.js has no tolerance-based assertions).
• collapses the if ( y === expected[i] ) { ... } else { ... } branch in each fixture loop into a single t.strictEqual( isAlmostSameValue( y, expected[ i ], N ), true, 'returns expected value' ) assertion, matching the idiom used in the already-merged migrations (e.g., stats/base/dists/gumbel/quantile).
• removes the now-unused abs and EPS requires and the delta/tol variables (including a stray tol = EPS; in test.factory.js).

Only test files are changed.

ULP bounds

File	Test (fixture)	Previous tolerance	ULP bound
test/test.logpdf.js	both_large	1.0 * EPS * abs( expected )	0
test/test.logpdf.js	large_scale	1.0 * EPS * abs( expected )	0
test/test.logpdf.js	large_shape	1.0 * EPS * abs( expected )	0
test/test.factory.js	all three	1.0 * EPS * abs( expected )	0
test/test.native.js	both_large / large_scale / large_shape	2.0 / 2.0 / 10.0 * EPS * abs( expected )	0

Each bound is the minimum integer N for which every fixture value passes. It was found by setting that one assertion to N (others at 64) and increasing N from 0 until the file passed. The minimum is 0 everywhere, so every fixture value is reproduced bit-for-bit. The suite was run twice at the final bounds with identical results (3023 passing assertions in test.logpdf.js and test.native.js, 3028 in test.factory.js, 0 failing), and the native addon was built so test.native.js actually ran. npx eslint on the test files is clean.

Related Issues

Does this pull request have any related issues?

This pull request has the following related issues:

• [RFC]: Migrate math/base/special packages from relative tolerance testing to ULP difference testing (tracking issue) #11352

Questions

Any questions for reviewers of this pull request?

No.

Other

Any other information relevant to this pull request? This may include screenshots, references, and/or implementation notes.

The ULP value is passed as a literal, as in the other merged migrations, rather than as a named constant. The pre-commit editorconfig step could not download its binary in this environment, so it was skipped; the diff only removes lines from tab-indented files.

Checklist

Please ensure the following tasks are completed before submitting this pull request.

• Read, understood, and followed the contributing guidelines.

AI Assistance

When authoring the changes proposed in this PR, did you use any kind of AI assistance?

• Yes
• No

If you answered "yes" above, how did you use AI assistance?

• Code generation (e.g., when writing an implementation or fixing a bug)
• Test/benchmark generation
• Documentation (including examples)
• Research and understanding

Disclosure

This PR was written primarily by Claude Code, running as an unattended scheduled task. It selected the package, studied previously migrated packages, performed the migration, and measured the minimum passing ULP bounds.

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@stdlib-js/reviewers

🤖 Generated with Claude Code

https://claude.ai/code/session_019dhnpndHupQsUA3fAyxi1g

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Generated by Claude Code

[stdlib-bot]

Coverage Report

Package	Statements	Branches	Functions	Lines
stats/base/dists/weibull/logpdf	$\\color{green}308/308$ $\\color{green}+100.00\\%$	$\\color{green}35/35$ $\\color{green}+100.00\\%$	$\\color{green}4/4$ $\\color{green}+100.00\\%$	$\\color{green}308/308$ $\\color{green}+100.00\\%$

The above coverage report was generated for the changes in this PR.