t6300: abstract away SHA-1-specific constants

Adjust the test so that it computes variables for object IDs instead of
using hard-coded hashes.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t6300-for-each-ref.sh

@@ -20,6 +20,10 @@ setdate_and_increment () {
 }
 
 test_expect_success setup '
+	test_oid_cache <<-EOF &&
+	disklen sha1:138
+	disklen sha256:154
+	EOF
 	setdate_and_increment &&
 	echo "Using $datestamp" > one &&
 	git add one &&
@@ -50,6 +54,9 @@ test_atom() {
 	"
 }
 
+hexlen=$(test_oid hexsz)
+disklen=$(test_oid disklen)
+
 test_atom head refname refs/heads/master
 test_atom head refname: refs/heads/master
 test_atom head refname:short master
@@ -82,9 +89,9 @@ test_atom head push:rstrip=-1 refs
 test_atom head push:strip=1 remotes/myfork/master
 test_atom head push:strip=-1 master
 test_atom head objecttype commit
-test_atom head objectsize 171
-test_atom head objectsize:disk 138
-test_atom head deltabase 0000000000000000000000000000000000000000
+test_atom head objectsize $((131 + hexlen))
+test_atom head objectsize:disk $disklen
+test_atom head deltabase $ZERO_OID
 test_atom head objectname $(git rev-parse refs/heads/master)
 test_atom head objectname:short $(git rev-parse --short refs/heads/master)
 test_atom head objectname:short=1 $(git rev-parse --short=1 refs/heads/master)
@@ -125,11 +132,11 @@ test_atom tag refname:short testtag
 test_atom tag upstream ''
 test_atom tag push ''
 test_atom tag objecttype tag
-test_atom tag objectsize 154
-test_atom tag objectsize:disk 138
-test_atom tag '*objectsize:disk' 138
-test_atom tag deltabase 0000000000000000000000000000000000000000
-test_atom tag '*deltabase' 0000000000000000000000000000000000000000
+test_atom tag objectsize $((114 + hexlen))
+test_atom tag objectsize:disk $disklen
+test_atom tag '*objectsize:disk' $disklen
+test_atom tag deltabase $ZERO_OID
+test_atom tag '*deltabase' $ZERO_OID
 test_atom tag objectname $(git rev-parse refs/tags/testtag)
 test_atom tag objectname:short $(git rev-parse --short refs/tags/testtag)
 test_atom head objectname:short=1 $(git rev-parse --short=1 refs/heads/master)
@@ -139,7 +146,7 @@ test_atom tag parent ''
 test_atom tag numparent ''
 test_atom tag object $(git rev-parse refs/tags/testtag^0)
 test_atom tag type 'commit'
-test_atom tag '*objectname' 'ea122842f48be4afb2d1fc6a4b96c05885ab7463'
+test_atom tag '*objectname' $(git rev-parse refs/tags/testtag^{})
 test_atom tag '*objecttype' 'commit'
 test_atom tag author ''
 test_atom tag authorname ''