reconsider "the way to run a crate's unit tests is `x test <crate>`"

[jyn514]

Summary

@ChrisDenton brought up to me the following thorny problem:

Say you are a libs contributor working on std. Right now, to run all relevant tests, the command you need is something like x test library tests/ui/std rustdoc-js-std. This is verbose and a little unreasonable to expect people to remember.

We would like to add an alias for this; x test std-tests could work. But now x test std does something people don't expect (only runs a subset of the std tests). If we change x test std to mean x test std-tests, then now we have an inconsistency between x test core, which only runs crate tests, and x test std, which means "run a superset of crate tests".

When I added unit tests in #95503, I wasn't really thinking about "run all the tests for an area", because we didn't have any equivalent of std-tests, then or now. But now that I've added it, the naming conflict is unfortunate. Maybe we should reconsider the naming here, and have the way to run unit tests for a crate be x test std-unit or something like that? Or only do this for library crates, and have x test rustc_resolve continue to mean "run the unit tests for rustc_resolve"? It could be nice to have x test rustc_resolve also imply x test tests/ui/resolve, though.

Command used

x test std
x test library
x test rustc_resolve

Expected behaviour

Actual behaviour

Bootstrap configuration (bootstrap.toml)

see above

Operating system

ubuntu 22.04, but this is a problem on all OSes

HEAD

a114bcf

[lolbinarycat]

I was just having this same thought recently, except with rustdoc, where the problem is even worse, due to how many test suites are involved.

[kpreid]

Speaking as an occasional contributor who hasn't learned all the corners of the codebase, it would be nice to have both of the following readily available:

• Run all tests in this directory
• Run all tests of the code in this directory

Perhaps exactly this distinction could be specified with a syntax, and an error produced when it's ambiguous:

./x test in:library/std   # explicit
./x test of:library/std   # explicit
./x test library/std      # error: ambiguous
./x test tests/ui/typeck  # unambiguous