test: migrate math/base/special/cexp to ULP-based assertions

[Planeshifter]

Resolves a part of #11352.

Description

What is the purpose of this pull request?

This pull request:

• Migrates math/base/special/cexp test cases from relative-tolerance (EPS-scaled delta/tol) comparisons to ULP-based assertions using @stdlib/assert/is-almost-same-value, per the RFC in [RFC]: Migrate math/base/special packages from relative tolerance testing to ULP difference testing (tracking issue) #11352.
• Updates both test/test.js and test/test.native.js.
• Measured the minimum ULP threshold that still passes over the full fixture set (pure_imaginary.json, general_complex.json), confirmed deterministic across two consecutive local runs:
  • test.js (pure JS implementation): 0 ULP for both the real and imaginary components (exact match against the reference fixtures).
  • test.native.js (native addon): 1 ULP for the real component (both fixture sets) and the imaginary component of the pure-imaginary fixture set; 2 ULP for the imaginary component of the general-complex fixture set, mirroring the pre-existing native implementation's wider tolerance (2.0 * EPS) for that specific case.

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.

• Only the two test files for math/base/special/cexp were changed; no other packages were touched.
• Verified: make test TESTS_FILTER=".*/math/base/special/cexp/.*" passes (2034/2034 for both test.js and the native addon build of test.native.js), and npx eslint is clean on both files.
• Opened as a draft so a maintainer/the repo owner can review before marking ready, given this RFC issue asks contributors to author these migrations manually; see the AI Assistance disclosure below.

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 written entirely by Claude Code (an automated, scheduled session), including discovering the candidate package, studying prior-art conversions (e.g. math/base/special/cinv), rewriting the test assertions, and empirically determining the ULP thresholds above. It is left as a draft specifically so a human can review it before it is considered for merge, given issue #11352 encourages contributors to author these migrations manually.

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@stdlib-js/reviewers

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Generated by Claude Code

[stdlib-bot]

Coverage Report

Package	Statements	Branches	Functions	Lines
math/base/special/cexp	$\\color{green}199/199$ $\\color{green}+100.00\\%$	$\\color{green}16/16$ $\\color{green}+100.00\\%$	$\\color{green}2/2$ $\\color{green}+100.00\\%$	$\\color{green}199/199$ $\\color{green}+100.00\\%$

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