tests: Add a test for link checkout speedup

tests/test-basic.sh

@@ -19,7 +19,7 @@
 
 set -e
 
-echo "1..34"
+echo "1..35"
 
 . $(dirname $0)/libtest.sh
 
@@ -253,4 +253,9 @@ ostree --repo=repo refs > reflist
 assert_not_file_has_content reflist '^test3$'
 echo "ok reflist --delete"
 
+cd ${test_tmpdir}
+rm -rf test2-checkout
+$OSTREE checkout test2 test2-checkout
+(cd test2-checkout && $OSTREE commit --link-checkout-speedup -b test2 -s "tmp")
+echo "ok commit with link speedup"