tests: use 'test_must_be_empty' instead of 'test ! -s'

diff --git a/t/t4150-am.sh b/t/t4150-am.sh
index 1ebc587f8fc0010713f52196206462fa915cbca5..38fe717c12c173d0744dd29e3691f3d9aa05b781 100755 (executable)
--- a/t/t4150-am.sh
+++ b/t/t4150-am.sh
@@ -651,7 +651,7 @@ test_expect_success 'am -3 -q is quiet' '
        git checkout -f lorem2 &&
        git reset base3way --hard &&
        git am -3 -q lorem-move.patch >output.out 2>&1 &&
-       ! test -s output.out
+       test_must_be_empty output.out
 '
 
 test_expect_success 'am pauses on conflict' '
@@ -874,7 +874,7 @@ test_expect_success 'am -q is quiet' '
        git checkout first &&
        test_tick &&
        git am -q <patch1 >output.out 2>&1 &&
-       ! test -s output.out
+       test_must_be_empty output.out
 '
 
 test_expect_success 'am empty-file does not infloop' '