From 95356789ee5e65abbdf3f354b8be4c79b196e8a1 Mon Sep 17 00:00:00 2001
From: Jeff King <peff@peff.net>
Date: Sat, 1 May 2021 10:03:25 -0400
Subject: t5300: check that we produced expected number of deltas

We pack a set of objects both with and without --window=0, assuming that
the 0-length window will cause us not to produce any deltas. Let's
confirm that this is the case.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 t/t5300-pack-object.sh | 23 ++++++++++++++++++++---
 1 file changed, 20 insertions(+), 3 deletions(-)

diff --git a/t/t5300-pack-object.sh b/t/t5300-pack-object.sh
index 1e10c832a6..887e2d8d88 100755
--- a/t/t5300-pack-object.sh
+++ b/t/t5300-pack-object.sh
@@ -34,8 +34,22 @@ test_expect_success 'setup' '
 	} >expect
 '
 
+# usage: check_deltas <stderr_from_pack_objects> <cmp_op> <nr_deltas>
+# e.g.: check_deltas stderr -gt 0
+check_deltas() {
+	deltas=$(perl -lne '/delta (\d+)/ and print $1' "$1") &&
+	shift &&
+	if ! test "$deltas" "$@"
+	then
+		echo >&2 "unexpected number of deltas (compared $delta $*)"
+		return 1
+	fi
+}
+
 test_expect_success 'pack without delta' '
-	packname_1=$(git pack-objects --window=0 test-1 <obj-list)
+	packname_1=$(git pack-objects --progress --window=0 test-1 \
+			<obj-list 2>stderr) &&
+	check_deltas stderr = 0
 '
 
 test_expect_success 'pack-objects with bogus arguments' '
@@ -62,7 +76,8 @@ test_expect_success 'unpack without delta' '
 '
 
 test_expect_success 'pack with REF_DELTA' '
-	packname_2=$(git pack-objects test-2 <obj-list)
+	packname_2=$(git pack-objects --progress test-2 <obj-list 2>stderr) &&
+	check_deltas stderr -gt 0
 '
 
 test_expect_success 'unpack with REF_DELTA' '
@@ -70,7 +85,9 @@ test_expect_success 'unpack with REF_DELTA' '
 '
 
 test_expect_success 'pack with OFS_DELTA' '
-	packname_3=$(git pack-objects --delta-base-offset test-3 <obj-list)
+	packname_3=$(git pack-objects --progress --delta-base-offset test-3 \
+			<obj-list 2>stderr) &&
+	check_deltas stderr -gt 0
 '
 
 test_expect_success 'unpack with OFS_DELTA' '
-- 
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