Changed Pkg.test to prioritise julia_args --threads over current process threads

[stemann]

Changed Pkg.test to prioritise julia_args --threads over current process threads

Ensures that tests run with threads, both when calling julia --project --threads=auto --eval 'using Pkg; Pkg.test()', and when calling julia --project --eval 'using Pkg; Pkg.test(; julia_args = ["--threads=auto"])'.

Similar to #4140

[IanButterworth]

Makes sense. Can you add a test

[stemann]

Not completely sure how to properly add this test, but what I am aiming for is something similar to running the following for the added TestThreads test package:

EXPECTED_NTHREADS=1 julia +nightly --project --eval 'using Pkg; Pkg.test()'

EXPECTED_NTHREADS=2 julia +nightly --project --threads=2 --eval 'using Pkg; Pkg.test()'

EXPECTED_NTHREADS=2 julia +nightly --project --eval 'using Pkg; Pkg.test(; julia_args=["--threads=2"])'

EXPECTED_NTHREADS=1 julia +nightly --project --threads=2 --eval 'using Pkg; Pkg.test(; julia_args=["--threads=1"])'

Edit: This is the behaviour on Julia 1.6, and 1.10.

[stemann]

I guess, one could also add:

EXPECTED_NTHREADS=2 JULIA_NUM_THREADS=2 julia +nightly --project --eval 'using Pkg; Pkg.test()'

EXPECTED_NTHREADS=2 julia +nightly --project --eval 'using Pkg; Pkg.test(; julia_args=Cmd(``; env=Dict("JULIA_NUM_THREADS" => 2)))'

EXPECTED_NTHREADS=1 JULIA_NUM_THREADS=2 julia +nightly --project --eval 'using Pkg; Pkg.test(; julia_args=Cmd(``; env=Dict("JULIA_NUM_THREADS" => 1)))'

[stemann]

Any suggestions for how to implement the tests?

[IanButterworth]

Take a look at existing test packages and add one that can be called by Pkg.test in tests.

[IanButterworth]

Just a passing comment that this should probably account for and test both threadpools

[stemann]

Did something change post-Julia-1.11, that remedied the issue with passing --threads=auto to the precompile process, as part of test? I.e., making the change in #4140 irrelevant for Julia 1.12+, cf. JuliaLang/julia#53572 (comment).

[stemann]

What about the other parts of the julia_args Cmd?

Is it safe to ignore julia_args.cpus, julia_args.dir, julia_args.flags (!= flags), and julia_args.ignorestatus?