test: migrate blas/base/scasum 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/scasum from relative tolerance assertions to ULP-based assertions, replacing the delta/tol computation in the isApprox helper with @stdlib/number/float32/base/assert/is-almost-same-value (the single-precision variant, matching the package's single-precision output and sibling blas/base/srotm).
• updates test/test.scasum.js, test/test.scasum.native.js, test/test.ndarray.js, and test/test.ndarray.native.js. Only test files are changed.
• uses a final ULP constant of ULP = 1 in every converted test.

ULP measurement

Each approximate assertion was swept from a high bound downward to the minimum integer that still passes. The measured minimum for every assertion in this package is 1 ULP:

Test	Assertion	Actual	Expected	Min. ULP
computes the sum ...	scasum( 4, x, 1 )	1.600000023841858	1.6	1
computes the sum ...	scasum( 3, x, 1 )	1.3000000715255737	1.3	1
supports specifying a stride	scasum( 4, x, 2 )	1.600000023841858	1.6	1
supports specifying a negative stride	scasum( 4, x, -1 )	28.899999618530273	28.9	1
ndarray: supports specifying complex access patterns	scasum( 4, x, -2, 6 )	1.600000023841858	1.6	1

ULP = 0 is not viable here because a zero bound degenerates to an exact SameValue comparison, while the expected values in these tests are double-precision literals (e.g. 1.6) rather than exactly representable single-precision values. Hence 1 is the tightest bound. The suite was run twice at the final bound to confirm deterministic results.

Test cases that already asserted exact equality via t.strictEqual (zero-N, view offsets, offset) were left untouched.

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?

The native (*.native.js) tests mirror the JavaScript ULP constants, following the convention in the already-migrated blas/base/drot, blas/base/drotm, and blas/base/srotm. The native add-on was not built in the environment used to author this change, so those tests were skipped locally and their bounds have not been empirically verified against the C implementation.

Other

Any other information relevant to this pull request? This may include screenshots, references, and/or implementation notes.

Opened as a draft pending CI, in particular the native add-on test runs.

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.

This PR was written by Claude Code running as an unattended scheduled task. The agent studied the already-migrated sibling packages (blas/base/dzasum, blas/base/srotm, blas/base/drot) to mirror the established idiom, applied the conversion, and determined the minimum ULP bound empirically by sweeping bounds against the fixture values.

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@stdlib-js/reviewers

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Generated by Claude Code

[stdlib-bot]

Hello! 👋

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Coverage Report

Package	Statements	Branches	Functions	Lines
blas/base/scasum	$\\color{green}369/369$ $\\color{green}+100.00\\%$	$\\color{green}17/17$ $\\color{green}+100.00\\%$	$\\color{green}4/4$ $\\color{green}+100.00\\%$	$\\color{green}369/369$ $\\color{green}+100.00\\%$

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

[kgryte]

The ULP values should be inlined.