test: migrate blas/base/wasm/zdrot 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 blas/base/wasm/zdrot from relative tolerance assertions to ULP difference assertions, per [RFC]: Migrate math/base/special packages from relative tolerance testing to ULP difference testing (tracking issue) #11352.
• replaces the EPS/abs based isApprox tolerance helper in test/test.main.js, test/test.ndarray.js, test/test.module.main.js, and test/test.module.ndarray.js with @stdlib/assert/is-almost-same-value, mirroring the already migrated blas/base/wasm/csrot and blas/base/wasm/zscal packages.

The isApprox helper now accepts a maximum allowed ULP difference instead of a relative tolerance:

function isApprox( t, actual, expected, ulp ) {
	var i;

	t.strictEqual( actual.length, expected.length, 'returns expected value' );
	for ( i = 0; i < expected.length; i++ ) {
		t.strictEqual( isAlmostSameValue( actual[ i ], expected[ i ], ulp ), true, 'returns expected value' );
	}
}

ULP bound: 1 ULP, applied uniformly at all 50 isApprox call sites (12 in test.main.js, 14 in test.ndarray.js, 10 in test.module.main.js, 14 in test.module.ndarray.js), replacing the previous 2.0 relative tolerance factor.

This is the measured minimum. The maximum observed ULP difference at every individual call site is exactly 1, so no call site can be tightened further: the full suite fails (16 failing assertions) at 0 ULP and passes at 1 ULP. The suite was run twice at the final bound to confirm determinism; all 536 assertions across the package's seven test files pass in both runs.

Only test files are modified; no implementation, documentation, or benchmark changes are included.

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 lint-editorconfig-files step could not run in the authoring environment, as it requires downloading the editorconfig-checker binary from GitHub releases, which was not reachable. EditorConfig conformance (tab indentation, LF line endings, no trailing whitespace, final newline) was verified manually instead. ESLint, using etc/eslint/.eslintrc.tests.js, passes cleanly on all four changed files.

Checklist

Please ensure the following tasks are completed before submitting this pull request.

• Read, understood, and followed the [contributing guidelines][contributing].

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. The test migration mirrors the idiom established in the already merged blas/base/wasm/csrot migration, and the 1 ULP bound was determined empirically by instrumenting every assertion to record its minimum passing ULP difference, then verifying the full suite twice at that bound.

---

@stdlib-js/reviewers

---

Generated by Claude Code

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Coverage Report

Package	Statements	Branches	Functions	Lines
blas/base/wasm/zdrot	$\\color{green}706/706$ $\\color{green}+100.00\\%$	$\\color{green}17/17$ $\\color{green}+100.00\\%$	$\\color{green}6/6$ $\\color{green}+100.00\\%$	$\\color{green}706/706$ $\\color{green}+100.00\\%$

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