test: add tests for C99 edge cases

[anandkaranubc]

Resolves None

Description

What is the purpose of this pull request?

This pull request:

• Completes the TODO on confirming the alignment of math/base/special/cabs with C99 conventions

Related Issues

Does this pull request have any related issues?

This pull request:

• resolves None

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.

---

@stdlib-js/reviewers

[stdlib-bot]

Coverage Report

Package	Statements	Branches	Functions	Lines
math/base/special/cabs	$\color{green}138/138$ $\color{green}+100.00\%$	$\color{green}5/5$ $\color{green}+100.00\%$	$\color{green}2/2$ $\color{green}+100.00\%$	$\color{green}138/138$ $\color{green}+100.00\%$

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

[anandkaranubc]

Also, based on the TODO comment referring to SciPy's implementation, I am still not sure why they perform an infinity check before a NaN check. They also specify that it's according to the C99 rules. However, testing with those values shows something different—if any of the arguments is NaN, the result is NaN.

Test results

No special comment has been made in the reference C99 documentation, and I couldn’t find anything in the ISO/IEC 9899:1999 that justifies this either.

cc: @kgryte

[kgryte]

@anandkaranubc See also https://data-apis.org/array-api/latest/API_specification/generated/array_api.abs.html#array_api.abs. The rule to check for infinity before NaN can be found in C99 hypot: https://en.cppreference.com/w/c/numeric/math/hypot.

[kgryte]

It's also possible that our hypot is not IEEE 754 compliant. We should double check, as our hypot does not match C99 atm.

[kgryte]

LGTM. Thanks, @anandkaranubc!