Create a TESTING.md document

[nikitawootten-nist]

User Story:

As an OSCAL team member, I need documentation describing our compliance with NIST's software publication checklist (see more in https://github.com/usnistgov/oscal-base/issues/1).

Goals:

• A description of the testing methodology for this project, and how tests can be run
  • A summary of what is and is not tested
  • An explanation of how to run and add new tests
  • A metric defining the desired code coverage
• Conformity to SA-11 and (some) enhancements
  • SA-11(1): GitHub's static code analysis action
  • SA-11(2): Dependabot?
  • SA-11(4): CODEOWNERS
  • SA-11(7)
  • ?

Dependencies:

This issue was formulated as a result of https://github.com/usnistgov/oscal-base/issues/1

Acceptance Criteria

• readme documentation affected by the changes in this issue have been updated.
• A Pull Request (PR) is submitted that fully addresses the goals of this User Story. This issue is referenced in the PR.
• The CI-CD build process runs without any reported errors on the PR. This can be confirmed by reviewing that all checks have passed in the PR.

Note

• This issue is part of Add support for profile tailoring OSCAL#43
• A "follow-up" to this issue may be to OSCALize this document into a component definition