It sets PYTHONPATH but doesn't include installed scripts in PATH.
commit 5eed45569cd54c87a16f967ec52fb5b363948818 Author: Michał Górny <mgorny@gentoo.org> AuthorDate: 2020-08-01 21:05:29 +0200 Commit: Michał Górny <mgorny@gentoo.org> CommitDate: 2020-08-09 19:10:16 +0200 distutils-r1.eclass: Set PATH in distutils_install_for_testing Make distutils_install_for_testing set PATH so that newly-installed scripts are available in the testing environment. Make PATH local in all sub-phases to make modifications safe. Signed-off-by: Michał Górny <mgorny@gentoo.org>