test_bucketspace.js should be renamed to test_nsfs_integrations.js test_s3_on_nsfs_flow.js or something similar as it is not actually a unit test file but it provides integration tests.
Full RPM/Linux flow tests - install, upgrade, health, syslog.
Metrics tests.
Add more existing s3 tests to nc_index.js (currently commented).
S3 concurrency tests - bucket/objects scale 1000. Concurrent ops example for buckets: create, list, delete.
CLI concurrency tests - bucket/account scale 1000. Concurrent ops example for buckets: create, list, delete, health.
Remove duplicate code - like exec_manage_cli() and other functions used by mocha/jest i different ways.
Environment info
Unit tests refactoring ideas