test: migrate stats/incr/nanprod 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 cases for stats/incr/nanprod from relative tolerance assertions to ULP-based assertions using @stdlib/assert/is-almost-same-value.

Two test cases (overflow may be transient and underflow may be transient) computed a delta/tol pair and asserted delta <= tol. Both now use

t.strictEqual( isAlmostSameValue( acc(), expected, 1 ), true, 'returns expected value' );

The @stdlib/math/base/special/abs and @stdlib/constants/float64/eps requires are removed, as they are no longer used anywhere in the file.

ULP bound: 1 for both test cases. This is the measured minimum: starting from a high bound and tightening, the suite passes at 1 and fails at 0 (both assertions fail at 0, confirming each result is exactly one ULP from its expected value). The suite was run twice at the final bound to confirm determinism — 3124 assertions passing both times, with no architecture- or FMA-dependent variation.

The chosen bound matches the sibling package stats/incr/prod, which uses 1 for the equivalent transient overflow/underflow test cases.

Only test/test.js is changed; there is no test/test.native.js for this package. make test TESTS_FILTER=".*/stats/incr/nanprod/.*" and make lint-javascript-tests TESTS_FILTER=".*/stats/incr/nanprod/.*" are both clean.

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.

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?

• 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 running as an unattended scheduled task. It studied the migration idiom from previously merged conversions (including the sibling package stats/incr/prod), applied the mechanical conversion, and determined the minimum passing ULP bound empirically by sweeping candidate values and re-running the suite.

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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/incr/nanprod	$\\color{green}128/128$ $\\color{green}+100.00\\%$	$\\color{green}7/7$ $\\color{green}+100.00\\%$	$\\color{green}2/2$ $\\color{green}+100.00\\%$	$\\color{green}128/128$ $\\color{green}+100.00\\%$

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