test: migrate stats/base/dists/hypergeometric/mean 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/hypergeometric/mean from relative tolerance testing to ULP difference testing, replacing the computed delta/tol comparisons with @stdlib/assert/is-almost-same-value.

The ULP bounds were tightened to the measured minimum over the full Julia fixture set (100 cases):

• test/test.js: 1 ULP. 80 of 100 fixture values are bit-exact; the maximum observed ULP difference is 1 (worst case N = 176, K = 100, n = 47, returning 26.704545454545457 vs. an expected 26.704545454545453). Lowering the bound to 0 fails 20 of the 100 assertions, so 1 is the minimum.
• test/test.native.js: 0 ULP. All 100 fixture values are bit-exact for the C implementation.

The differing bounds follow from the JS and C implementations evaluating the mean with different operation orders, as described in JS vs C return values: JavaScript computes n * ( K / N ) (two roundings), while C computes ( (double)n * (double)K ) / (double)N, where the product is exact for the fixture inputs and the single division is correctly rounded.

Verification:

• make test TESTS_FILTER=".*/stats/base/dists/hypergeometric/mean/.*" passes (120 assertions in test.js, 108 in test.native.js, 0 failing). The native addon was built locally via make install-node-addons NODE_ADDONS_PATTERN="hypergeometric/mean", so the native tests were executed rather than skipped.
• The suite was run twice at the final bounds with identical results, confirming determinism.
• make lint-javascript-tests TESTS_FILTER=".*/stats/base/dists/hypergeometric/mean/.*" is clean.
• 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?

• test/test.native.js uses a bound of 0 because the C implementation reproduces every fixture value exactly, while test/test.js requires 1. Happy to align both files on 1 if a uniform per-package bound is preferred over the per-file measured minimum.

Other

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

The lint-editorconfig-files target could not be run in this environment, as the editorconfig-checker wrapper downloads its binary from a GitHub release that was not reachable. The changed files were checked manually against .editorconfig instead: LF line endings, tab indentation, no trailing whitespace, and a 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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Disclosure

If you answered "yes" to using AI assistance, please provide a short disclosure indicating how you used AI assistance. This helps reviewers determine how much scrutiny to apply when reviewing your contribution. Example disclosures: "This PR was written primarily by Claude Code." or "I consulted ChatGPT to understand the codebase, but the proposed changes were fully authored manually by myself.".

This PR was authored by Claude Code, which selected the package, mirrored the migration idiom from previously converted packages, measured the minimum passing ULP bounds against the fixture set, and ran the package tests and test linter locally.

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https://claude.ai/code/session_01RYRomVwa3KVswQ1745T3N7

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[stdlib-bot]

Coverage Report

Package	Statements	Branches	Functions	Lines
stats/base/dists/hypergeometric/mean	$\\color{green}194/194$ $\\color{green}+100.00\\%$	$\\color{green}13/13$ $\\color{green}+100.00\\%$	$\\color{green}2/2$ $\\color{green}+100.00\\%$	$\\color{green}194/194$ $\\color{green}+100.00\\%$

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/hypergeometric/mean, 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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