diff --git a/system/perl-5.28.1-0.build.sh b/system/perl-5.28.1-0.build.sh
index b09c68a..1797084 100755
--- a/system/perl-5.28.1-0.build.sh
+++ b/system/perl-5.28.1-0.build.sh
@@ -11,7 +11,9 @@ set -xe
 PKG=perl
 VERSION=5.28.1
 BUILD=0
+
 PREFIX=/usr/local/system/$PKG-$VERSION-$BUILD
+if [ -n "$TESTING" ]; then PREFIX=/dev/shm/$PKG-$VERSION-$BUILD ; fi
 
 mkdir -p $PREFIX
 cat >$PREFIX/profile <<-EOF