diff --git a/testcode/do-tests.sh b/testcode/do-tests.sh
index 83bf40080..b1fcd040d 100755
--- a/testcode/do-tests.sh
+++ b/testcode/do-tests.sh
@@ -7,16 +7,12 @@ cd testdata;
 for test in `ls *.tpkg`; do
 	SKIP=0
 	if echo $NEED_SPLINT | grep $test >/dev/null; then
-		if which splint >/dev/null 2>&1; then
-			:
-		else
+		if test ! -x "`which splint`"; then
 			SKIP=1;
 		fi
 	fi
 	if echo $NEED_DOXYGEN | grep $test >/dev/null; then
-		if which doxygen >/dev/null 2>&1; then
-			:
-		else
+		if test ! -x "`which doxygen`"; then
 			SKIP=1;
 		fi
 	fi