test: migrate stats/incr/nanmmpe 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/nanmmpe from relative tolerance testing to ULP difference testing, as proposed in [RFC]: Migrate math/base/special packages from relative tolerance testing to ULP difference testing (tracking issue) #11352.

Specifically, in test/test.js:

• adds the @stdlib/assert/is-almost-same-value import and removes the now unused @stdlib/math/base/special/abs and @stdlib/constants/float64/eps imports.
• removes the delta/tol computation (and the corresponding variable declarations) in the test which checks that the accumulator function computes a moving mean percentage error incrementally.
• replaces the t.equal( delta <= tol, ... ) tolerance branch with t.strictEqual( isAlmostSameValue( actual, expected[i], 1 ), true, 'returns expected value' );.

The final ULP constant is 1, which is the measured minimum. Starting from a loose bound of 64 and tightening over the full fixture set, 1 is the smallest integer which passes: at 0, three of the six fixture assertions fail. The suite was run twice at the final bound to confirm the result is deterministic (98 passing on both runs).

For reference, the non-NaN sibling package, stats/incr/mmpe, which shares the same fixture values, was previously migrated using the same 1 ULP bound.

No changes were made to the exact-equality assertions elsewhere in the file, as those compare exactly representable values and are correct as-is.

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.

Verification performed:

• make test TESTS_FILTER=".*/stats/incr/nanmmpe/.*" → 98 passing, 0 failing (run twice at the final ULP bound).
• Linting introduces no new findings: make lint-javascript-files reports an identical set of 13 pre-existing problems both before and after this change (these stem from the target applying the source ESLint overrides to a test file).
• The only file changed is lib/node_modules/@stdlib/stats/incr/nanmmpe/test/test.js.

This package has no test/test.native.js, so only test/test.js required updating.

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 authored by Claude Code. It studied the already-migrated sibling package stats/incr/mmpe to mirror the established project idiom, applied the migration, and determined the minimum passing ULP bound empirically by running the test suite across decreasing bounds.

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@stdlib-js/reviewers

🤖 Generated with Claude Code

https://claude.ai/code/session_019LRi44byiqKb1zH1gx1krz

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Coverage Report

Package	Statements	Branches	Functions	Lines
stats/incr/nanmmpe	$\\color{green}149/149$ $\\color{green}+100.00\\%$	$\\color{green}8/8$ $\\color{green}+100.00\\%$	$\\color{green}2/2$ $\\color{green}+100.00\\%$	$\\color{green}149/149$ $\\color{green}+100.00\\%$

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