fsck tests: test for garbage appended to a loose object

There wasn't any output tests for this scenario, let's ensure that we
don't regress on it in the changes that come after this.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t1450-fsck.sh

@@ -93,6 +93,26 @@ test_expect_success 'object with hash and type mismatch' '
 	)
 '
 
+test_expect_success POSIXPERM 'zlib corrupt loose object output ' '
+	git init --bare corrupt-loose-output &&
+	(
+		cd corrupt-loose-output &&
+		oid=$(git hash-object -w --stdin --literally </dev/null) &&
+		oidf=objects/$(test_oid_to_path "$oid") &&
+		chmod 755 $oidf &&
+		echo extra garbage >>$oidf &&
+
+		cat >expect.error <<-EOF &&
+		error: garbage at end of loose object '\''$oid'\''
+		error: unable to unpack contents of ./$oidf
+		error: $oid: object corrupt or missing: ./$oidf
+		EOF
+		test_must_fail git fsck 2>actual &&
+		grep ^error: actual >error &&
+		test_cmp expect.error error
+	)
+'
+
 test_expect_success 'branch pointing to non-commit' '
 	git rev-parse HEAD^{tree} >.git/refs/heads/invalid &&
 	test_when_finished "git update-ref -d refs/heads/invalid" &&