nix: native tests fail to due to small temporary filesystem

[brianhenn]

When running make test_native in the nix shell, the regression tests fail on my vm due to nix assigning the environment variable TMPDIR to a smallish (3GB) nix user filesystem, which runs out of space. The solution seems to be to assign TMPDIR back to /tmp: NixOS/nix#1009 (comment) in default.nix

[nbren12]

Thanks for finding this. So pytest listens to TMDDIR? If so we can set it the env var in the shellHook here:

fv3gfs-fortran/nix/fv3/default.nix

Line 168 in 075d515

export PATH=$(pwd)/FV3:$PATH

.