Unit tests for color extension

[AdrianBinDC]

Write unit tests

Description

• Add unit tests for Color+Extension.swift

Motivation and Context

Add unit tests to facilitate automated testing and enable quick identification of breaking changes.

How Has This Been Tested?

Unit tests only, no changes to codebase.

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Non-functional change (Updating Documentation, CI automation, etc..)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.

[AdrianBinDC]

@AppPear I rebased off your new-version branch and resolved the conflict. All tests pass.

[AppPear]

Thanks very much appreciated!