submodule--helper: show usage for "-h"

diff --git a/t/t2013-checkout-submodule.sh b/t/t2013-checkout-submodule.sh
index 6847f7582234d656563f867976a64142a3a01621..e8f70b806f110c75b9bda5bca0af6732be391fcd 100755 (executable)
--- a/t/t2013-checkout-submodule.sh
+++ b/t/t2013-checkout-submodule.sh
@@ -63,6 +63,12 @@ test_expect_success '"checkout <submodule>" honors submodule.*.ignore from .git/
        ! test -s actual
 '
 
+KNOWN_FAILURE_DIRECTORY_SUBMODULE_CONFLICTS=1
+KNOWN_FAILURE_SUBMODULE_RECURSIVE_NESTED=1
+test_submodule_switch_recursing "git checkout --recurse-submodules"
+
+test_submodule_forced_switch_recursing "git checkout -f --recurse-submodules"
+
 test_submodule_switch "git checkout"
 
 test_submodule_forced_switch "git checkout -f"