Bug: Unit test directory ./source/tests missing or purposely omitted?

[tcmnal]

I don't know if this issue qualifies strictly as a bug, but it is unexpected behaviour for the solution nonetheless.

Describe the bug
I was previously working with v2.5.3. I recently synced my fork with the latest v2.7.1. The latest version seems to be missing the unit tests. Now running './deployment/run-unit-tests.sh' as part of my build, as suggested in README.md, is purposeless since no unit tests are found and ran.

Output:
...
445 | ============================= test session starts ==============================
446 | platform linux -- Python 3.11.9, pytest-6.2.4, py-1.11.0, pluggy-0.13.1 -- /codebuild/output/src14648982/src/testing-venv/bin/python3
447 | cachedir: .pytest_cache
448 | rootdir: /codebuild/output/src14648982/src, configfile: pytest.ini
449 | plugins: mock-3.5.1
450 | collecting ... collected 0 items
451 |  
452 | ============================ no tests ran in 0.02s =============================

To Reproduce
Clone v2.7.1 of repo.
Follow instructions in ./README.md to run unit tests:

chmod +x ./deployment/run-unit-tests.sh
./deployment/run-unit-tests.sh

Expected behavior
I expected unit tests to be located somewhere within the directory and ran.

Please complete the following information about the solution:

• Version: 2.7.0 +
• Region: N/A
• Was the solution modified from the version published on this repository? Yes, but I don't believe that is relevant to this particular issue
• If the answer to the previous question was yes, are the changes available on GitHub? No
• Have you checked your service quotas for the sevices this solution uses? No, not applicable
• Were there any errors in the CloudWatch Logs? No

Additional context
If unit tests are available but not published to this public repository, I would ask for that to be reconsidered, since they are useful for validating the solution.

[JamesActually]

Unit tests are run internally, but are not included in the release distributed to GitHub. It would make sense for us to include them. I've created a backlog item for the team to explore adding them here so customers can also run these tests.

[tcmnal]

@JamesActually This would be appreciated, since they were previously included. This repo's README also makes reference to them in section 'Running unit tests for customization'. My use case is as described; running the unit tests "to make sure added customization passes the tests".