When emerging twisted-names-13.2.0, with FEATURES="test", i got the following error: >>> Test phase: dev-python/twisted-names-13.2.0 * python2_7: running distutils-r1_run_phase python_test /usr/bin/python2.7 setup.py egg_info --egg-base=/var/tmp/portage/dev-python/twisted-names-13.2.0/work/TwistedNames-13.2.0-python2_7/test/lib install --home=/var/tmp/portage/dev-python/twisted-names-13.2.0/work/TwistedNames-13.2.0-python2_7/test --install-li b=/var/tmp/portage/dev-python/twisted-names-13.2.0/work/TwistedNames-13.2.0-python2_7/test/lib --install-scripts=/var/tmp/portage/dev-python/twisted-names-13.2.0/work/TwistedNames-13.2.0-python2_7/test/scripts usage: setup.py [global_opts] cmd1 [cmd1_opts] [cmd2 [cmd2_opts] ...] or: setup.py --help [cmd1 cmd2 ...] or: setup.py --help-commands or: setup.py cmd --help error: invalid command 'egg_info' egg_info setup.py command is added by distutils-r1 in distutils_install_for_testing
I can confirm this for all jupyter packages. Thus, this isn't an problem with dev-python/twisted-names, but seems to be a problem with setuptools or the eclass.
The bug also affects dev-vcs/mercurial-3.8.4. Extracting the source tar-ball of mercurial and running "python2.7 setup.py egg_info" yields the above mentioned error. Interesting enough, the setup.py contained in the tarball of dev-python/zope-interface-4.3.2 accepts the command "egg_info" without any complaint. So I think it's partly related to setuptools/eclass but also to the specific packages in question.
Mass reaping of bugs filed against split Twisted packages. Those packages are replaced by dev-python/twisted, and we can't expect any failures to be fixed upstream for the old versions.