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
Handle additional edge cases arising from test(1)’s lack of reserved words.
For example, left parenthesis followed by an operator could indicate
either
* string comparison of a literal left parenthesis, e.g. `( = foo`
* parenthesized expression using an operator as a literal, e.g. `( = != foo )`
`LANGUAGE=C` is not enough, `LC_ALL=C` is needed as the environment
variable that overrides all the other localization settings.
e.g.
```bash
$ LANGUAGE=C id foobar
id: ‘foobar’: no such user
$ LC_ALL=C id foobar
id: 'foobar': no such user
```
* replace `LANGUAGE` with `LC_ALL` as environment variable in the tests
* fix the the date string of affected uutils
* replace `‘` and `’` with `'`
When invoked via '[' name, last argument must be ']' or we bail out with
syntax error. Then the trailing ']' is simply disregarded and processing
happens like usual.
- add `==` as undocumented alias of `=`
- handle negated comparison of `=` as literal
- negation generally applies to only the first expression of a Boolean chain,
except when combining evaluation of two literal strings
- Replace the parser with a recursive descent implementation that handles
parentheses and produces a stack of operations in postfix order.
Parsing now operates directly on OsStrings passed by the uucore framework.
- Replace the dispatch mechanism with a stack machine operating on the
symbol stack produced by the parser.
- Add tests for parenthesized expressions.
- Begin testing character encoding handling.
