diff --git a/templates/install-wp-tests.sh b/templates/install-wp-tests.sh
index 87180fce1..f8d67be80 100644
--- a/templates/install-wp-tests.sh
+++ b/templates/install-wp-tests.sh
@@ -12,8 +12,9 @@ DB_HOST=${4-localhost}
 WP_VERSION=${5-latest}
 SKIP_DB_CREATE=${6-false}
 
-WP_TESTS_DIR=${WP_TESTS_DIR-/tmp/wordpress-tests-lib}
-WP_CORE_DIR=${WP_CORE_DIR-/tmp/wordpress/}
+TMPDIR=${TMPDIR-/tmp}
+WP_TESTS_DIR=${WP_TESTS_DIR-$TMPDIR/wordpress-tests-lib}
+WP_CORE_DIR=${WP_CORE_DIR-$TMPDIR/wordpress/}
 
 download() {
     if [ `which curl` ]; then
@@ -57,23 +58,23 @@ install_wp() {
 	mkdir -p $WP_CORE_DIR
 
 	if [[ $WP_VERSION == 'nightly' || $WP_VERSION == 'trunk' ]]; then
-		mkdir -p /tmp/wordpress-nightly
-		download https://wordpress.org/nightly-builds/wordpress-latest.zip  /tmp/wordpress-nightly/wordpress-nightly.zip
-		unzip -q /tmp/wordpress-nightly/wordpress-nightly.zip -d /tmp/wordpress-nightly/
-		mv /tmp/wordpress-nightly/wordpress/* $WP_CORE_DIR
+		mkdir -p $TMPDIR/wordpress-nightly
+		download https://wordpress.org/nightly-builds/wordpress-latest.zip  $TMPDIR/wordpress-nightly/wordpress-nightly.zip
+		unzip -q $TMPDIR/wordpress-nightly/wordpress-nightly.zip -d $TMPDIR/wordpress-nightly/
+		mv $TMPDIR/wordpress-nightly/wordpress/* $WP_CORE_DIR
 	else
 		if [ $WP_VERSION == 'latest' ]; then
 			local ARCHIVE_NAME='latest'
 		elif [[ $WP_VERSION =~ [0-9]+\.[0-9]+ ]]; then
 			# https serves multiple offers, whereas http serves single.
-			download https://api.wordpress.org/core/version-check/1.7/ /tmp/wp-latest.json
+			download https://api.wordpress.org/core/version-check/1.7/ $TMPDIR/wp-latest.json
 			if [[ $WP_VERSION =~ [0-9]+\.[0-9]+\.[0] ]]; then
 				# version x.x.0 means the first release of the major version, so strip off the .0 and download version x.x
 				LATEST_VERSION=${WP_VERSION%??}
 			else
 				# otherwise, scan the releases and get the most up to date minor version of the major release
 				local VERSION_ESCAPED=`echo $WP_VERSION | sed 's/\./\\\\./g'`
-				LATEST_VERSION=$(grep -o '"version":"'$VERSION_ESCAPED'[^"]*' /tmp/wp-latest.json | sed 's/"version":"//' | head -1)
+				LATEST_VERSION=$(grep -o '"version":"'$VERSION_ESCAPED'[^"]*' $TMPDIR/wp-latest.json | sed 's/"version":"//' | head -1)
 			fi
 			if [[ -z "$LATEST_VERSION" ]]; then
 				local ARCHIVE_NAME="wordpress-$WP_VERSION"
@@ -83,8 +84,8 @@ install_wp() {
 		else
 			local ARCHIVE_NAME="wordpress-$WP_VERSION"
 		fi
-		download https://wordpress.org/${ARCHIVE_NAME}.tar.gz  /tmp/wordpress.tar.gz
-		tar --strip-components=1 -zxmf /tmp/wordpress.tar.gz -C $WP_CORE_DIR
+		download https://wordpress.org/${ARCHIVE_NAME}.tar.gz  $TMPDIR/wordpress.tar.gz
+		tar --strip-components=1 -zxmf $TMPDIR/wordpress.tar.gz -C $WP_CORE_DIR
 	fi
 
 	download https://raw.github.com/markoheijnen/wp-mysqli/master/db.php $WP_CORE_DIR/wp-content/db.php