@@ -228,8 +228,10 @@ install_test_suite() {
 		download https://raw.githubusercontent.com/WordPress/wordpress-develop/${ref}/wp-tests-config-sample.php "$WP_TESTS_DIR"/wp-tests-config.php
 		# remove all forward slashes in the end
 		WP_CORE_DIR=$(echo $WP_CORE_DIR | sed "s:/\+$::")
-		sed $ioption "s:dirname( __FILE__ ) . '/src/':'$WP_CORE_DIR/':" "$WP_TESTS_DIR"/wp-tests-config.php
-		sed $ioption "s:__DIR__ . '/src/':'$WP_CORE_DIR/':" "$WP_TESTS_DIR"/wp-tests-config.php
+		# escape special sed replacement characters in $WP_CORE_DIR (backslash, pipe, ampersand)
+		WP_CORE_DIR_ESCAPED=$(printf '%s' "$WP_CORE_DIR" | sed 's/[\\|&]/\\&/g')
+		sed $ioption "s|dirname( __FILE__ ) . '/src/'|'${WP_CORE_DIR_ESCAPED}/'|" "$WP_TESTS_DIR"/wp-tests-config.php
+		sed $ioption "s|__DIR__ . '/src/'|'${WP_CORE_DIR_ESCAPED}/'|" "$WP_TESTS_DIR"/wp-tests-config.php
 		sed $ioption "s/youremptytestdbnamehere/$DB_NAME/" "$WP_TESTS_DIR"/wp-tests-config.php
 		sed $ioption "s/yourusernamehere/$DB_USER/" "$WP_TESTS_DIR"/wp-tests-config.php
 		sed $ioption "s/yourpasswordhere/$DB_PASS/" "$WP_TESTS_DIR"/wp-tests-config.php