* Move the user and group resolution to the behavior decoding instead of
re-running on every file/directory creation. Simplifies code.
* Update error output to match GNU coreutils.
* Add tests to verify invalid owner and group.
* Re-factor the copy function chown into a function that can be re-used.
* Fix bug where the group overwrote the user.
* Add chown compatibility to follow GNU coreutils.
* Reduce two chown calls to a single syscall only when needed.
* Fixes#4361
Summary of changes in UCommand:
* Extend UCommand by builder methods and simplify methods in TestScenario
* Simplify code structures where possible. Add documentation.
* Store bin_path as PathBuf and util_name as String in all structs
* Remove UCommand::util and make bin_path, temp_dir private
* Rename UCommand::with_limit -> UCommand::limit
Summary of changes in TestScenario:
* Rename some parameters in TestScenario methods to be more descriptive
* Remove ucmd_keepenv, cmd_keepenv from TestScenario. Use UCommand::keep_env instead.
This mirrors a recent commit that introduced the `Dest` enum and a
simplified `Output` struct. These changes allow us to add new types of
inputs and output more easily.
Summary of changes in tests/util:
* Introduce global constant TESTS_BINARY holding the path to `coreutils`
* Implement running an arbitrary command in a sh or cmd shell per default.
* Implement std::fmt::Display for UCommand.
* Change usages of UCommand::util_name from &Option<OsStr> to Option<OsStr>
* `UCommand::new_from_tmp`: Use OsStr directly instead of TempDir -> String -> OsStr
* Collect arguments in `UCommand::args` field
* Build environment variables in `UCommand` itself instead of `std::process::Command`
* Move building of std::process:Command from fields in UCommand to own method `build`
* Remove assertions of UCommand::has_run in arg, args and env.
Summary of changes in tests/by-util:
* Remove usages of UCommand::raw. Fix tests to use UCommand::to_string.
* test_test: Adjust test_invalid_utf8_integer_compare to use `UCommand::args`
* test_chmod: run_single_test
* test_pwd: symlinked_env
* test_cp:
Fix the usage of &Option<OsStr> in `test_src_base_dot`
Refactor test_src_base_dot to not use UCommand::new but ts.ucmd() instead
* tests/util: Fix documentation of UCommand::stderr_only and usage_error
* tests/util: Remove trimming from CmdResult::stdout_matches and stdout_does_not_match. Fix tests.
The tests are fixed to match the trailing newline instead of ignoring it.
* nproc: replace num_cpus crate with std:🧵:available_parallelism
* nproc: unwrap Result for Windows
* nproc: if thread::available_parallelism results in err return 1
* nproc: wrap the call to available_parallelism into a function
* nproc: remove comment in the wrong place
* nproc: fix style violation
* nproc: fix comment, refers to the new function
