t6501: avoid hard-coded objects

This test contains hard-coded invalid object IDs.  Make it hash size
independent by generating invalid object IDs using the translation
tables.  Add a setup target to ensure the output of test_oid_init is
checked properly.

Signed-off-by: brian m. carlson <[email protected]>
Reviewed-by: Eric Sunshine <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: bk2204

t/t6501-freshen-objects.sh

@@ -128,9 +128,9 @@ for repack in '' true; do
 done
 
 test_expect_success 'do not complain about existing broken links (commit)' '
-	cat >broken-commit <<-\EOF &&
-	tree 0000000000000000000000000000000000000001
-	parent 0000000000000000000000000000000000000002
+	cat >broken-commit <<-EOF &&
+	tree $(test_oid 001)
+	parent $(test_oid 002)
 	author whatever <[email protected]> 1234 -0000
 	committer whatever <[email protected]> 1234 -0000
 
@@ -143,8 +143,8 @@ test_expect_success 'do not complain about existing broken links (commit)' '
 '
 
 test_expect_success 'do not complain about existing broken links (tree)' '
-	cat >broken-tree <<-\EOF &&
-	100644 blob 0000000000000000000000000000000000000003	foo
+	cat >broken-tree <<-EOF &&
+	100644 blob $(test_oid 003)	foo
 	EOF
 	tree=$(git mktree --missing <broken-tree) &&
 	git gc -q 2>stderr &&
@@ -153,8 +153,8 @@ test_expect_success 'do not complain about existing broken links (tree)' '
 '
 
 test_expect_success 'do not complain about existing broken links (tag)' '
-	cat >broken-tag <<-\EOF &&
-	object 0000000000000000000000000000000000000004
+	cat >broken-tag <<-EOF &&
+	object $(test_oid 004)
 	type commit
 	tag broken
 	tagger whatever <[email protected]> 1234 -0000