t4011: 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/t4011-diff-symlink.sh

@@ -9,11 +9,24 @@ test_description='Test diff of symlinks.
 . ./test-lib.sh
 . "$TEST_DIRECTORY"/diff-lib.sh
 
+# Print the short OID of a symlink with the given name.
+symlink_oid () {
+	local oid=$(printf "%s" "$1" | git hash-object --stdin) &&
+	git rev-parse --short "$oid"
+}
+
+# Print the short OID of the given file.
+short_oid () {
+	local oid=$(git hash-object "$1") &&
+	git rev-parse --short "$oid"
+}
+
 test_expect_success 'diff new symlink and file' '
-	cat >expected <<-\EOF &&
+	symlink=$(symlink_oid xyzzy) &&
+	cat >expected <<-EOF &&
 	diff --git a/frotz b/frotz
 	new file mode 120000
-	index 0000000..7c465af
+	index 0000000..$symlink
 	--- /dev/null
 	+++ b/frotz
 	@@ -0,0 +1 @@
@@ -21,7 +34,7 @@ test_expect_success 'diff new symlink and file' '
 	\ No newline at end of file
 	diff --git a/nitfol b/nitfol
 	new file mode 100644
-	index 0000000..7c465af
+	index 0000000..$symlink
 	--- /dev/null
 	+++ b/nitfol
 	@@ -0,0 +1 @@
@@ -46,10 +59,10 @@ test_expect_success 'diff unchanged symlink and file'  '
 '
 
 test_expect_success 'diff removed symlink and file' '
-	cat >expected <<-\EOF &&
+	cat >expected <<-EOF &&
 	diff --git a/frotz b/frotz
 	deleted file mode 120000
-	index 7c465af..0000000
+	index $symlink..0000000
 	--- a/frotz
 	+++ /dev/null
 	@@ -1 +0,0 @@
@@ -57,7 +70,7 @@ test_expect_success 'diff removed symlink and file' '
 	\ No newline at end of file
 	diff --git a/nitfol b/nitfol
 	deleted file mode 100644
-	index 7c465af..0000000
+	index $symlink..0000000
 	--- a/nitfol
 	+++ /dev/null
 	@@ -1 +0,0 @@
@@ -90,9 +103,10 @@ test_expect_success 'diff identical, but newly created symlink and file' '
 '
 
 test_expect_success 'diff different symlink and file' '
-	cat >expected <<-\EOF &&
+	new=$(symlink_oid yxyyz) &&
+	cat >expected <<-EOF &&
 	diff --git a/frotz b/frotz
-	index 7c465af..df1db54 120000
+	index $symlink..$new 120000
 	--- a/frotz
 	+++ b/frotz
 	@@ -1 +1 @@
@@ -101,7 +115,7 @@ test_expect_success 'diff different symlink and file' '
 	+yxyyz
 	\ No newline at end of file
 	diff --git a/nitfol b/nitfol
-	index 7c465af..df1db54 100644
+	index $symlink..$new 100644
 	--- a/nitfol
 	+++ b/nitfol
 	@@ -1 +1 @@
@@ -137,14 +151,16 @@ test_expect_success SYMLINKS 'setup symlinks with attributes' '
 '
 
 test_expect_success SYMLINKS 'symlinks do not respect userdiff config by path' '
-	cat >expect <<-\EOF &&
+	file=$(short_oid file.bin) &&
+	link=$(symlink_oid file.bin) &&
+	cat >expect <<-EOF &&
 	diff --git a/file.bin b/file.bin
 	new file mode 100644
-	index 0000000..d95f3ad
+	index 0000000..$file
 	Binary files /dev/null and b/file.bin differ
 	diff --git a/link.bin b/link.bin
 	new file mode 120000
-	index 0000000..dce41ec
+	index 0000000..$link
 	--- /dev/null
 	+++ b/link.bin
 	@@ -0,0 +1 @@