fix: Move test datasets to tests/artifacts/testdata instead of tests/data

[dushyantbehl]

Description of the change

The test datasets residing in tests/data folder should be moved to tests/arifacts directory to keep all test artifacts at one location, and keep the folders under tests/ directory contain only test code other than a singe artifact folder.

In this light renames tests/data to tests/artifacts/testdata and make minor changes to test case utilising the test data.

Related issue number

N/A

How to verify the PR

Run make to ensure all fmt lint and tests pass.

Was the PR tested

Tested by ensuring all test cases pass.

• I have ensured all unit tests pass

[github-actions]

Thanks for making a pull request! 😃
One of the maintainers will review and advise on the next steps.

[willmj]

LGTM