test harness: Fix $skip_test support, broken yesterday.

It was broken by commit e6eea1f,
"test harness: Don't leak options from test files to the test harness.".

Author: danielshahaf

tests/test-highlighting.zsh

@@ -124,25 +124,26 @@ run_test_internal() {
   local -a expected_region_highlight region_highlight
 
   local ARG="$1"
+  local RETURN=""
   () {
     setopt localoptions
     . "$srcdir"/"$ARG"
 
     # WARNING: The remainder of this anonymous function will run with the test's options in effect
 
-    (( $#skip_test )) && { print -r -- "1..0 # SKIP $skip_test"; return; }
+    (( $#skip_test )) && { print -r -- "1..0 # SKIP $skip_test"; return ${RETURN:=0}; }
 
     # Check the data declares $PREBUFFER or $BUFFER.
-    [[ -z $PREBUFFER && -z $BUFFER ]] && { echo >&2 "Bail out! On ${(qq)1}: Either 'PREBUFFER' or 'BUFFER' must be declared and non-blank"; return 1; }
+    [[ -z $PREBUFFER && -z $BUFFER ]] && { echo >&2 "Bail out! On ${(qq)1}: Either 'PREBUFFER' or 'BUFFER' must be declared and non-blank"; return ${RETURN:=1}; }
     # Check the data declares $expected_region_highlight.
-    (( $+expected_region_highlight == 0 )) && { echo >&2 "Bail out! On ${(qq)1}: 'expected_region_highlight' is not declared."; return 1; }
+    (( $+expected_region_highlight == 0 )) && { echo >&2 "Bail out! On ${(qq)1}: 'expected_region_highlight' is not declared."; return ${RETURN:=1}; }
 
     # Set sane defaults for ZLE variables
     : ${CURSOR=$#BUFFER} ${PENDING=0} ${WIDGET=z-sy-h-test-harness-test-widget}
 
     # Process the data.
     _zsh_highlight
-  }
+  }; [[ -z $RETURN ]] || return $RETURN
   unset ARG
 
   if (( unsorted )); then