* chore: Remove `backup` target from Makefile
- The `backup` target is no longer serving any value to us. It was made redundant with changes added in Oct 2020.
- `clean` target inline docs revised.
- `.gitignore` remove test lines that are no longer valid.
* chore: Parallel test target split to multi-line
* tests(fix): Test `setup.sh` with temporary config dir
The `no_containers.bats` test has many redundant test cases already covered by `setup-cli`. They're basically identical. Removed all but one.
This removes some config dirs that were being explicitly created instead of using the test helper to generate a directory that can be used to test the `-p` option instead.
* ci: Ensure tests are run when `Makefile` is modified
Allows for using `load` with an absolute path instead of a relative one, which makes it possible to group tests into different directories.
Parallel tests differ slightly, loading the newer `helper/common.bash` and `helper/setup.bash` files instead of the older `test_helper/common.bash` which serial tests continue to use.
- `test_helper.bats` needs more work than this PR provides to be compatible with parallel tests, so must remain as a serial test for now.
- `spam_bounced.bats` had failures as a serial test, but works well converted to a parallel test in a future commit.
