feat: add missing tests to ndarray/base/includes

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• task: lint_filenames status: passed
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• task: lint_markdown status: na
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• task: lint_javascript_src status: na
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• task: lint_javascript_tests status: passed
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Progresses #2656 .

Description

What is the purpose of this pull request?

This pull request:

• adds missing tests for 100% test code coverage.

Related Issues

Does this pull request have any related issues?

This pull request:

• progresses [RFC]: achieve ndarray API parity with built-in JavaScript arrays  #2656

Questions

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No.

Other

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No.

Checklist

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

• Read, understood, and followed the contributing guidelines.

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Coverage Report

Package	Statements	Branches	Functions	Lines
ndarray/base/includes	$\color{red}12450/12461$ $\color{green}+99.91\%$	$\color{red}1420/1425$ $\color{green}+99.65\%$	$\color{green}64/64$ $\color{green}+100.00\%$	$\color{red}12450/12461$ $\color{green}+99.91\%$

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

[kgryte]

LGTM after some small edits.