fix: clean up sandbox directories after tests

[raymondfeng]

This is rework of #5720.

There are 3 commits:

1. Use unique sandbox subdirs for parallel testing (must-have) Extracted to #5747

2. Add KEEP_TEST_SANDBOX env var to keep files for sandbox.delete (nice-to-have)

3. Add after hook to delete test sandbox directories (should-have)

Checklist

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• npm test passes on your machine
• New tests added or existing tests modified to cover all changes
• Code conforms with the style guide
• API Documentation in code was updated
• Documentation in /docs/site was updated
• Affected artifact templates in packages/cli were updated
• Affected example projects in examples/* were updated

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[bajtos]

I am little bit reluctant to implement env-based behavior inside delete, I think it could be surprising. Can we implement a new method please and find a descriptive name that will make it more clear what is happening or where it should be used?

Since our motivation is to run this code in after/afterEach hooks, maybe cleanupAfterTests could be a better name?

after('delete sandbox', () => sandbox.cleanupAfterTests());

When I was trying to troubleshoot test failures, I found there were many left-over subdirectories under .sandbox. This prevented me from knowing which directory I should look into.

I would like to investigate a way how to let the sandbox cleanup routine detect when a test failed and print a helpful message (something along the lines "sandbox for test XYZ is in directory ABC"). This is probably out of scope of this PR, but if we introduce a new method like cleanupAfterTests, then it will be easier to enhance the behavior in the future.

Do we want to honor this env var in @loopback/testlab for both reset and delete?

I think we should apply ENV-specific behavior in delete only. reset is meant to be called before the tests, I think the test would fail when the sanbox was not cleared because of ENV config.

[stale]

This pull request has been marked stale because it has not seen activity within two months. It will be closed within 14 days of being stale unless there is new activity.

[stale]

This pull request has been closed due to continued inactivity. If you are interested in finishing the proposed changes, then feel free to re-open this pull request or open a new one.