[Service]
Type=oneshot
# This should work, as we explicitly disable the effect of ReadOnlyPaths=
ExecStart=+/bin/touch /tmp/thisisasimpletest
# This should also work, as we do not disable the effect of ReadOnlyPaths= but invert the exit code
ExecStart=/bin/sh -x -c '! /bin/touch /tmp/thisisasimpletest'
ExecStart=+/bin/rm /tmp/thisisasimpletest
ReadOnlyPaths=/tmp