Open
Description
Makefile runs tests under zsh -f.
The test harness entry points should enforce that zsh had been launched with -f and bail out if that's not the case. [[ $- == *f* ]] should work.
This would trigger if someone tries to run zsh tests/foo.zsh by hand, or to source that file from an interactive shell (that hadn't been started with -f; this caveat is probably fine).
(Related: the #! lines can't use -f because they use #!.../env zsh and passing multiple arguments is unportable.)