When `NIX_DAEMON_PACKAGE` is set, make all the tests use the Nix daemon.
That way we can test every piece of Nix functionality both with and
without the daemon.
Tests for which using the daemon isn’t possible or doesn’t make sens can
selectively be disabled with `needLocalStore`
Fixes this random failure:
error: hash mismatch in fixed-output derivation '/tmp/nix-shell.EUgAVU/nix-test/tests/check/store/sfps3l3c5n7dabpx34kigxnfhmrwk2h6-dummy.drv':
specified: sha256-47DEQpj8HBSa+/TImW+5JCeuQeRkm5NMpJWZG3hSuFU=
got: sha256-0qhPS4tlCTfsj3PNi+LHSt1akRumTfJ0WO2CKdqASiY=
which happens because multiple tests were writing to ./dummy.
A test case for correct handling of temporary directory deletion that
was added to check.sh as part of PR #2689 was initially disabled for
Darwin because of a directory permission issue in PR #2688.
Now that the issue in PR #2688 is fixed, this commit enables the test
case for Darwin.
With --check and the --keep-failed (-K) flag, the temporary directory
was being retained regardless of whether the build was successful and
reproducible. This removes the temporary directory, as expected, on
a reproducible check build.
Added tests to verify that temporary build directories are not
retained unnecessarily, particularly when using --check with
--keep-failed.
