Feature request: install "test-depends" only for direct dependencies

[skaji]

Context

When I develop a Raku distribution "My-Module", I should prepare runtime/build/test dependencies for "My-Module" first.

Currently

zef install --/test --deps-only .

does not install "test-depends" for "My-Module".

Yes, if I execute "zef" by

zef install --/test --test-depends --deps-only .

"test-depends" are installed, but I don't want to install all "test-depends", but I just want to install "test-depends" only for "My-Module".

Expected Behavior

Introduce a new option to install "test-depends" only for direct dependencies, or

zef install --/test --deps-only .

install the direct "test-depends".

Actual Behavior

See "Context" section.

Steps to Reproduce

See "Context" section.

Your Environment

❯ raku -v
This is Rakudo version 2020.07 built on MoarVM version 2020.07
implementing Raku 6.d.

❯ zef list --installed
===> Found via /Users/skaji/env/p6env/versions/rakudo-2020.07/share/perl6/core
CORE:ver<6.d>:auth<perl>
===> Found via /Users/skaji/env/p6env/versions/rakudo-2020.07/share/perl6/site
zef:ver<0.8.5>:auth<github:ugexe>:api<0>