In the last line of run_emacs, exec the emacs process.
With one fork less the process list is (also) neater.
#
# --load Force loading of notmuch.el and test-lib.el
#
# --load Force loading of notmuch.el and test-lib.el
-emacs --no-init-file --no-site-file \
+exec emacs --no-init-file --no-site-file \
--directory "$TEST_DIRECTORY/../emacs" --load notmuch.el \
--directory "$TEST_DIRECTORY" --load test-lib.el \
"\$@"
--directory "$TEST_DIRECTORY/../emacs" --load notmuch.el \
--directory "$TEST_DIRECTORY" --load test-lib.el \
"\$@"