test: migrate stats/base/dists/geometric/skewness to ULP-based assertions

[kgryte]

Resolves a part of #11352.

Description

What is the purpose of this pull request?

This pull request:

• migrates the tests for stats/base/dists/geometric/skewness from relative tolerance testing to ULP difference testing, per [RFC]: Migrate math/base/special packages from relative tolerance testing to ULP difference testing (tracking issue) #11352.
• replaces the y === expected[i] / delta <= tol branch in the Julia fixture loops of test/test.js and test/test.native.js with t.strictEqual( isAlmostSameValue( y, expected[ i ], 0 ), true, 'returns expected value' );.
• adds the @stdlib/assert/is-almost-same-value require and drops the now unused @stdlib/math/base/special/abs and @stdlib/constants/float64/eps requires.

Final ULP constant: 0 (used in both test/test.js and test/test.native.js).

This is the measured minimum. The bound was found by measuring the per-fixture ULP difference with @stdlib/number/float64/base/ulp-difference across the full 1000-element Julia fixture set: the largest observed difference is 0, i.e., every returned value is bit-identical to its expected value, so no smaller bound exists. Starting from a high bound and lowering it therefore terminates at 0. The suite was run twice at the final value with identical results (1007/1007 passing), so there is no FMA/arch variation here.

A bound of 0 is consistent with already-migrated sibling packages whose fixtures also match exactly — e.g. stats/base/dists/binomial/kurtosis (a464e88), which likewise migrated to isAlmostSameValue( y, expected[ i ], 0 ) in both its JS and native test files. The implementation is a single expression, ( 2.0-p ) / sqrt( 1.0-p ), and src/main.c evaluates the identical expression with the same operation order, so the native add-on is expected to return the same values; the same bound is therefore used in the native test file.

Only the two test files are changed.

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.

• make test TESTS_FILTER=".*/stats/base/dists/geometric/skewness/.*" → 1007 passing, 0 failing for test/test.js; test/test.native.js skips, as the native add-on is not built in this environment. Run twice at the final ULP value to confirm determinism.
• Linting was run with the repository's own ESLint configuration over both changed files and is clean.
• Note on environment: make install-node-modules fails here because es-object-atoms@^1.1.2 is not published (the reachable registry has at most 1.1.1). This is a pre-existing dependency-resolution failure unrelated to this change; the dependency tree was installed with that transitive version pinned to 1.1.1 so that the project's own make test and ESLint configuration could be used.
• The editorconfig-checker step could not execute (its binary is downloaded from GitHub releases, which is unavailable here); both files were verified manually against .editorconfig (LF line endings, UTF-8, tab indentation, no trailing whitespace, final newline).

Checklist

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

• Read, understood, and followed the contributing guidelines.

AI Assistance

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• Yes
• No

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This PR was authored by Claude Code, running as an unattended scheduled task. Claude studied #11352 and the already-migrated sibling packages to mirror the established idiom, applied the migration, and determined the ULP bound empirically by measuring the per-fixture ULP difference rather than guessing it.

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https://claude.ai/code/session_01QG7gEdBDDNd41avDBtd3ge

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[stdlib-bot]

Coverage Report

Package	Statements	Branches	Functions	Lines
stats/base/dists/geometric/skewness	$\\color{green}166/166$ $\\color{green}+100.00\\%$	$\\color{green}9/9$ $\\color{green}+100.00\\%$	$\\color{green}2/2$ $\\color{green}+100.00\\%$	$\\color{green}166/166$ $\\color{green}+100.00\\%$

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

[Planeshifter]

⚠️ Issue Reference Review

An automated check found potentially unrelated issue/PR references in this PR:

Reference	Assessment	Reasoning
#11352	suspicious	Issue #11352 is an RFC explicitly scoped to migrating math/base/special packages from relative-tolerance to ULP-based testing (its own instructions say to search for a package "in math/base/special"). This PR migrates tests for stats/base/dists/geometric/skewness, which is outside the issue's stated scope.

Why this matters: GitHub automatically closes issues referenced with
closing keywords (Resolves, Closes, Fixes) when the PR is merged. Incorrect
references can accidentally close unrelated issues.

What to do:

• If the reference is correct, no action needed. This check may produce
  false positives.
• If the reference is incorrect, please update your PR description.

This assessment was generated by an AI model and is informational only.

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