tests/du: run test_du_time with TZ=UTC.

[eggpi]

Hi,

When running tests locally, I noticed that test_du_time fails because it expects the output to be 1h offset from what the tool produces:

$ cargo test --features "du touch" --no-default-features
...
---- test_du::test_du_time stdout ----
run: /Users/guilherme/src/coreutils/target/debug/coreutils touch -a -t 201505150000 date_test
run: /Users/guilherme/src/coreutils/target/debug/coreutils touch -m -t 201606160000 date_test
run: /Users/guilherme/src/coreutils/target/debug/coreutils du --time date_test
thread 'test_du::test_du_time' panicked at 'assertion failed: `(left == right)`

Diff < left / right > :
<0	2016-06-16 01:00	date_test
>0	2016-06-16 00:00	date_test


', tests/by-util/test_du.rs:409:12


failures:
    test_du::test_du_time

test result: FAILED. 85 passed; 1 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.82s

I believe the test assumes it is running on a machine with UTC timezone. I am in UTC + 1, which the tool output is correctly aware of. This PR changes the test to also expect local times.

Apologies if this is not very idiomatic, I am fairly new to Rust and obviously open to iterating on this 😄

Thanks in advance for the review!

[eggpi]

Fixed linter errors (hopefully).

[tertsdiepraam]

This makes sense, though it is a bit unfortunate that we have to do it this way, because now everyone can only test their own timezone. It would be better if we could specify the timezone in the test somehow. I wonder if that's possible.

[github-actions]

GNU testsuite comparison:

GNU test failed: tests/tail-2/inotify-dir-recreate. tests/tail-2/inotify-dir-recreate is passing on 'main'. Maybe you have to rebase?

[eggpi]

I could implement support for the TZ environment variable in du and use that to lock the test to UTC?

Testing this on a UTC Linux system:

$ du --version
du (GNU coreutils) 8.30
Copyright (C) 2018 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <https://gnu.org/licenses/gpl.html>.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

Written by Torbjorn Granlund, David MacKenzie, Paul Eggert,
and Jim Meyering.
$ du --time /etc/lsb-release
4	2022-08-22 10:53	/etc/lsb-release
$ TZ=UTC-5 du --time /etc/lsb-release
4	2022-08-22 15:53	/etc/lsb-release

What do you think?

[tertsdiepraam]

That should actually already work! That's because libc respects that variable and chrono uses libc:

❯ TZ=UTC-5 cargo run -q -- du --time Cargo.toml
20      2023-02-26 18:02        Cargo.toml
❯ cargo run -q -- du --time Cargo.toml
20      2023-02-26 14:02        Cargo.toml

So maybe we run the tests with TZ=UTC? Does that work? We could actually make that a variable that's added by default. Though, we'd have to change some other tests in that case. Let's start by just trying to add it here.

[eggpi]

I've changed this specific test to set TZ=UTC across all of the commands it invokes, I assume that's what you mean as the first step? This does seem to work fine.

[tertsdiepraam]

Nice! That's indeed what I meant.

[github-actions]

GNU testsuite comparison:

Congrats! The gnu test tests/tail-2/inotify-dir-recreate is no longer failing!

[eggpi]

Great! And after another encounter with the linter, this should be good now.

[tertsdiepraam]

Looks great! Could you add a comment on why it was necessary to add that variable for people who read the code without the context of the issue or this PR?

[eggpi]

Sure thing, done!

[sylvestre]

thanks