Overwrite allowed on Travis with open connection

[bjcairns]

On Travis-CI, build 6 failed because the test suite failed with the following report:

  ── 1. Failure: create_schema_db() fails to overwrite when db is connected (@test
  `{ ... }` did not throw an error.
  
  ══ testthat results  ═══════════════════════════════════════════════════════════
  OK: 19 SKIPPED: 1 WARNINGS: 1 FAILED: 1
  1. Failure: create_schema_db() fails to overwrite when db is connected (@test-create-schema-db.R#73) 

The failing test passes on my local Win10 OS, so maybe this is an OS issue?

The current work-around is to skip the test except on Windows, but it would be nice to know whether this goes deeper, e.g. if on Linux systems file.remove() works even when there is an open database connection. If so, some more robust way to check for open connections would be nice to have.

[elreda]

It seems to be an OS thing indeed. On MacOS for example, file.remove() has no problem deleting a file with an open database connection.

Based on the answer below on SO, running lsof on the file could be one way to "manually" check for open connections on Unix systems before trying to remove the file.
https://stackoverflow.com/questions/12138260

[bjcairns]

Going to close this - planning to migrate to GitHub Actions (per #34) and will see where that leaves us.