test: migrate stats/incr/nanmpe 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/incr/nanmpe from relative tolerance assertions (delta <= tol, where tol = C * EPS * abs( expected )) to ULP-based assertions using @stdlib/assert/is-almost-same-value, as proposed in [RFC]: Migrate math/base/special packages from relative tolerance testing to ULP difference testing (tracking issue) #11352.

Two test cases were migrated, and, in each case, the ULP bound was tightened to the minimum passing integer value:

Test case	Previous tolerance	ULP bound
the accumulator function incrementally computes the mean percentage error, ignoring NaN values	10.0 * EPS * abs( expected )	1
if not provided an input value, the accumulator function returns the current mean percentage error	1.0 * EPS * abs( expected )	1

The bounds were determined by starting from a high ULP allowance (64) and lowering the value until the minimum passing integer was found. For both test cases, lowering the bound to 0 causes that test case to fail, and thus 1 is minimal in each case. The test suite was run twice at the final bounds in order to confirm determinism (11/11 assertions passing in each run).

Notes:

• In the first test case, the previous actual === expected branch is no longer necessary, as isAlmostSameValue short-circuits on strict equality and thus already handles the iterations in which a NaN input leaves the accumulated value unchanged.
• The package does not provide a native implementation, and thus only test/test.js required updating.

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

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No.

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?

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• No

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• Code generation (e.g., when writing an implementation or fixing a bug)
• Test/benchmark generation
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Disclosure

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This PR was authored by Claude Code, which performed the test migration, measured the minimum passing ULP bounds, and ran the test and lint suites locally.

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@stdlib-js/reviewers

🤖 Generated with Claude Code

https://claude.ai/code/session_011wXHMLyS4pbZfSTXKCMyoX

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Generated by Claude Code

[stdlib-bot]

Hello! 👋

We've noticed that you've been opening a number of PRs addressing good first issues. Thank you for your interest and enthusiasm!

Now that you've made a few contributions, we suggest no longer working on good first issues. Instead, we encourage you to prioritize cleaning up any PRs which have yet to be merged and then proceed to work on more involved tasks.

Not only does this ensure that other new contributors can work on things and get ramped up on all things stdlib, it also ensures that you can spend your time on more challenging problems. 🚀

For ideas for future PRs, feel free to search the codebase for TODOs and FIXMEs and be sure to check out other open issues on the issue tracker. Cheers!

[stdlib-bot]

Coverage Report

Package	Statements	Branches	Functions	Lines
stats/incr/nanmpe	$\\color{green}129/129$ $\\color{green}+100.00\\%$	$\\color{green}7/7$ $\\color{green}+100.00\\%$	$\\color{green}2/2$ $\\color{green}+100.00\\%$	$\\color{green}129/129$ $\\color{green}+100.00\\%$

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