test: test_must_be_empty helper

diff --git a/t/t7400-submodule-basic.sh b/t/t7400-submodule-basic.sh
index 2683cba7e3f0ba7fbb7ea1752a39a6068fc91718..0055da965ca189f8ecb220e1a916c0b6714eb2b2 100755 (executable)
--- a/t/t7400-submodule-basic.sh
+++ b/t/t7400-submodule-basic.sh
@@ -78,7 +78,7 @@ test_expect_success 'submodule add' '
        (
                cd addtest &&
                git submodule add -q "$submodurl" submod >actual &&
-               test ! -s actual &&
+               test_must_be_empty actual &&
                echo "gitdir: ../.git/modules/submod" >expect &&
                test_cmp expect submod/.git &&
                (
@@ -308,7 +308,7 @@ test_expect_success 'update should work when path is an empty dir' '
 
        mkdir init &&
        git submodule update -q >update.out &&
-       test ! -s update.out &&
+       test_must_be_empty update.out &&
 
        inspect init &&
        test_cmp expect head-sha1
@@ -696,7 +696,7 @@ test_expect_success 'submodule add --name allows to replace a submodule with ano
                rm -rf repo &&
                git rm repo &&
                git submodule add -q --name repo_new "$submodurl/bare.git" repo >actual &&
-               test ! -s actual &&
+               test_must_be_empty actual &&
                echo "gitdir: ../.git/modules/submod" >expect &&
                test_cmp expect submod/.git &&
                (