When a package test suite wants to write to $HOME

d/elpa-test:

    ert_eval = (setq user-emacs-directory (make-temp-file "foo-test" 'dir-flag))

Rebuild all elpa-* packages in unstable against new Emacs in experimental

    aptitude search "~Aunstable~n^elpa-" -F"%e" | while read p; do sbuild --extra-repository='deb http://deb.debian.org/debian experimental main' --build-dep-resolver=aspcud --add-depends="emacs (>= 1:26)" --add-depends="emacs-common (>= 1:26)" --add-depends="emacs-bin-common (>= 1:26)" --add-depends="emacs-nox (>= 1:26)" "$p"; done

You can then run autopkgtest on all the changes files (untested!):

    for f in *.changes; do autopkgtest --setup-commands="echo >>/etc/apt/sources.list deb http://deb.debian.org/debian experimental main" --setup-commands="apt-get update" --setup-commands="apt-get install emacs/experimental" "$f" -l "$f.autopkgtest.log"; done