test: migrate stats/base/snanstdevtk to ULP-based assertions

[Planeshifter]

Resolves a part of #11352.

Description

What is the purpose of this pull request?

This pull request:

• migrates the stats/base/snanstdevtk test suite from the computed EPS/tolerance idiom (delta = abs( v - expected ); tol = 1.0 * EPS * abs( expected ); t.strictEqual( delta <= tol, ... )) to ULP-difference assertions using @stdlib/number/float32/base/assert/is-almost-same-value (isAlmostSameValuef), per [RFC]: Migrate math/base/special packages from relative tolerance testing to ULP difference testing (tracking issue) #11352.
• updates test/test.snanstdevtk.js, test/test.snanstdevtk.native.js, test/test.ndarray.js, and test/test.ndarray.native.js (the four files containing the tolerance idiom).
• the tightest ULP bound was determined empirically: starting from a high bound and lowering it, 1 is the minimum integer ULP distance for which all assertions in all four files pass; 0 fails 2 of the 36 assertions in each file. This matches the ULP bound already settled on for the sibling package stats/base/snanstdev (see PR test: migrate stats/base/snanstdev to ULP-based assertions #15216), whose test files follow an identical pattern.
• verified determinism by running each of the four test files twice at ULP 1 with identical (all-passing) results.

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.

Only the four test files were changed; no new dependency was introduced (@stdlib/number/float32/base/assert/is-almost-same-value already exists in the monorepo and is already used by other converted packages, e.g. stats/base/snanstdev). npx eslint on the changed files reports no issues, and make test TESTS_FILTER=".*/stats/base/snanstdevtk/.*" passes (36/36 in each JS test file; native variants report 0 tests, as expected when the native addon is not built in this environment).

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

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 written primarily by Claude Code, running as an unattended scheduled task: it discovered the candidate package, studied prior art from already-merged ULP-migration PRs (including #15216 for the sibling snanstdev package), performed the conversion, and empirically determined the tightest ULP bound.

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🤖 Generated with Claude Code

https://claude.ai/code/session_01WLQVoEVhUdPCfyaqueCuD5

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Coverage Report

Package	Statements	Branches	Functions	Lines
stats/base/snanstdevtk	$\\color{green}365/365$ $\\color{green}+100.00\\%$	$\\color{green}14/14$ $\\color{green}+100.00\\%$	$\\color{green}4/4$ $\\color{green}+100.00\\%$	$\\color{green}365/365$ $\\color{green}+100.00\\%$

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