+test_failure_with_unknown_submodule () {
+ test_must_fail git submodule $1 no-such-submodule 2>output.err &&
+ grep "^error: .*no-such-submodule" output.err
+}
+
+test_expect_success 'init should fail with unknown submodule' '
+ test_failure_with_unknown_submodule init
+'
+
+test_expect_success 'update should fail with unknown submodule' '
+ test_failure_with_unknown_submodule update
+'
+
+test_expect_success 'status should fail with unknown submodule' '
+ test_failure_with_unknown_submodule status
+'
+
+test_expect_success 'sync should fail with unknown submodule' '
+ test_failure_with_unknown_submodule sync
+'
+