function commandline
    if test $argv[1] = '-ct'
        echo --long4\n-4
    else if test $argv[1] = '-cpo'
        echo cmd\n-z\n-bc\n--long1\narg1\n-d\narg2\n--long2
    end
end

__fish_contains_opt -s z
or echo fails to find -z

__fish_contains_opt -s c
or echo fails to find -c

__fish_contains_opt -s x
and echo should not have found -x

__fish_contains_opt -s x -s z
or echo fails to find -z

__fish_contains_opt -s x -s c
or echo fails to find -c

__fish_contains_opt -s x long1
or echo fails to find --long1

__fish_contains_opt long2
or echo fails to find --long2

__fish_contains_opt long1 long2
or echo fails to find --long1 or --long2

__fish_contains_opt long3
and echo should not have found --long3

__fish_contains_opt -s 4 long4
or echo fails to find -4

__fish_contains_opt long4
and echo should not have found --long4

__fish_contains_opt arg1
and echo should not have found --arg1

__fish_contains_opt -s a
and echo should not have found -a

# This should result in message written to stderr and an error status.
__fish_contains_opt -x w
and '"__fish_contains_opt -x w" should not have succeeded'

true