# check whether function $`$counts$()`$ exists

# and whether counts$($x$)$ returns a list of length $2($for the input x $=-3$:$6)$

x $=-3$:$6$

if $($test$\_$that$($desc$=$"Sorry, functions $`$counts$`$ was not created correctly", code$=\{$

expect$\_$equal$($is$.$function$($counts$),$ TRUE$)$

$\})!=$ TRUE$)$ stop$("$Sorry$,$ functions $`$counts$`$ was not created correctly"$)$

if $($test$\_$that$($desc$="",$ code$=\{$

expect$\_$equal$($length$($counts$($x$)),2)$

$\})!=$ TRUE$)$ stop$("$Sorry$,$ for x$=-3$:$6,$ length of the returned list is not $2")$