Use `set -u` and `set -o pipefail` to catch accidental mistakes and
failures more strongly.
- `set -u` catches the use of undefined variables
- `set -o pipefail` catches failures (like `set -e`) earlier in the
pipeline.
This makes the tests a bit more robust. It is nice to read code not
worrying about these spurious success paths (via uncaught) errors
undermining the tests. Indeed, I caught some bugs doing this.
There are a few tests where we run a command that should fail, and then
search its output to make sure the failure message is one that we
expect. Before, since the `grep` was the last command in the pipeline
the exit code of those failing programs was silently ignored. Now with
`set -o pipefail` it won't be, and we have to do something so the
expected failure doesn't accidentally fail the test.
To do that we use `expect` and a new `expectStderr` to check for the
exact failing exit code. See the comments on each for why.
`grep -q` is replaced with `grepQuiet`, see the comments on that
function for why.
`grep -v` when we just want the exit code is replaced with `grepInverse,
see the comments on that function for why.
`grep -q -v` together is, surprise surprise, replaced with
`grepQuietInverse`, which is both combined.
Co-authored-by: Robert Hensing <roberth@users.noreply.github.com>
Split `common.sh` into the vars and functions definitions vs starting
the daemon (and possibly other initialization logic). This way,
`init.sh` can just `source` the former. Trying to start the daemon
before `nix.conf` is written will fail because `nix daemon` requires
`--experimental-features 'nix-command'`.
`killDaemon` is idempotent, so it's safe to call when no daemon is
running.
`startDaemon` and `killDaemon` use the PID (which is now exported to
subshells) to decide whether there is work to be done, rather than
`NIX_REMOTE`, which might conceivably be set differently even if a
daemon is running.
`startDaemon` and `killDaemon` can save/restore the old `NIX_REMOTE` as
`NIX_REMOTE_OLD`.
`init.sh` kills daemon before deleting everything (including the daemon
socket).
