test: migrate stats/base/dists/erlang/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 test suite for stats/base/dists/erlang/mean from relative-tolerance comparisons to ULP-based assertions using @stdlib/assert/is-almost-same-value.
• Replaces the abs( y - expected[i] ) <= tol (where tol = 1.0 * EPS * abs( expected[i] )) idiom, along with its y === expected[i] fast-path branch, with t.strictEqual( isAlmostSameValue( y, expected[ i ], 1 ), true, 'returns expected value' ) and removes the now-unused abs and EPS imports.
• Applies the same change to both test/test.js and test/test.native.js.

The ULP bound was tightened to the minimum integer which passes over the full fixture set (200 fixture values): 1 ULP, for both test/test.js and test/test.native.js. The bound is genuinely minimal — at a bound of 0 ULPs, 44 of the 200 fixture values fail for both the JavaScript and the native implementation, so the bound cannot be lowered further.

The JavaScript and C implementations agree exactly here: sweeping each fixture value individually, both require a maximum of 1 ULP and both diverge from the Julia fixtures on the same 44 values, which is consistent with both computing a single division k / lambda and the fixtures having been generated in a different order of operations.

The native addon was built locally so that test/test.native.js actually executed rather than skipping. Both suites were run twice at the final bound and pass deterministically (217 assertions in test/test.js and 215 in test/test.native.js, per run, no failures). Only the test files are modified.

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 repository's editorconfig-checker lint step could not run in this environment, as the tool is downloaded on demand from a third-party GitHub release which was unreachable from the sandbox. The two changed files were instead verified by hand against .editorconfig (LF endings, UTF-8, tab indentation, no trailing whitespace, final newline). ESLint (tests configuration), the license-header lint, and the filename lint all ran and passed.

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

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This PR was authored by Claude Code, following the migration pattern established in prior ULP-conversion PRs. The minimum ULP bound was measured empirically against the package's fixtures.

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@stdlib-js/reviewers

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Generated by Claude Code

[stdlib-bot]

Coverage Report

Package	Statements	Branches	Functions	Lines
stats/base/dists/erlang/mean	$\\color{green}199/199$ $\\color{green}+100.00\\%$	$\\color{green}9/9$ $\\color{green}+100.00\\%$	$\\color{green}2/2$ $\\color{green}+100.00\\%$	$\\color{green}199/199$ $\\color{green}+100.00\\%$

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