[PATCH] t5004: avoid using tar for empty packages

["Carlo Marcelo Arenas Belón" <carenas@gmail.com>]

ea2d20d4c2 ("t5004: avoid using tar for checking emptiness of archive",
2013-05-09), introduced a fake empty tar archive to allow for portable
tests of emptiness without having to invoke tar

4318094047 ("archive: don't add empty directories to archives", 2017-09-13)
changed the expected result for its tests from one containing an empty
directory to a plain empty archive but the portable test wasn't updated
resulting on them failing again in (at least) NetBSD and OpenBSD

Signed-off-by: Carlo Marcelo Arenas Belón <carenas@gmail.com>
---
 t/t5004-archive-corner-cases.sh | 17 ++++++++---------
 1 file changed, 8 insertions(+), 9 deletions(-)

diff --git a/t/t5004-archive-corner-cases.sh b/t/t5004-archive-corner-cases.sh
index ced44355ca..271eb5a1fd 100755
--- a/t/t5004-archive-corner-cases.sh
+++ b/t/t5004-archive-corner-cases.sh
@@ -3,8 +3,12 @@
 test_description='test corner cases of git-archive'
 . ./test-lib.sh
 
-test_expect_success 'create commit with empty tree' '
-	git commit --allow-empty -m foo
+# the 10knuls.tar file is used to test for an empty git generated tar
+# without having to invoke tar because an otherwise valid empty GNU tar
+# will be considered broken by {Open,Net}BSD tar
+test_expect_success 'create commit with empty tree and fake empty tar' '
+	git commit --allow-empty -m foo &&
+	perl -e "print \"\\0\" x 10240" >10knuls.tar
 '
 
 # Make a dir and clean it up afterwards
@@ -47,7 +51,6 @@ test_expect_success HEADER_ONLY_TAR_OK 'tar archive of commit with empty tree' '
 
 test_expect_success 'tar archive of empty tree is empty' '
 	git archive --format=tar HEAD: >empty.tar &&
-	perl -e "print \"\\0\" x 10240" >10knuls.tar &&
 	test_cmp_bin 10knuls.tar empty.tar
 '
 
@@ -106,16 +109,12 @@ test_expect_success 'create a commit with an empty subtree' '
 
 test_expect_success 'archive empty subtree with no pathspec' '
 	git archive --format=tar $root_tree >subtree-all.tar &&
-	make_dir extract &&
-	"$TAR" xf subtree-all.tar -C extract &&
-	check_dir extract
+	test_cmp_bin 10knuls.tar subtree-all.tar
 '
 
 test_expect_success 'archive empty subtree by direct pathspec' '
 	git archive --format=tar $root_tree -- sub >subtree-path.tar &&
-	make_dir extract &&
-	"$TAR" xf subtree-path.tar -C extract &&
-	check_dir extract
+	test_cmp_bin 10knuls.tar subtree-path.tar
 '
 
 ZIPINFO=zipinfo
-- 
2.20.0.rc2