[PATCH 2/2] t: use commit_body to extract commit message bodies

[Shlok Kulshreshtha <diy2903@gmail.com>]

Replace the "git cat-file commit | sed" idiom with commit_body across the
test suite: 60 sites in 11 files. The idiom appears in four equivalent
spellings -- piped or written to a file first, "sed -e" or plain "sed",
"\$" or "$" in the address -- all producing byte-identical output; they
all collapse to the same commit_body call.

Two sites needed more than a mechanical substitution:

* t7600.sh ("merge --no-ff --edit") greps the raw commit object for a
  phrase before stripping its header for the final comparison. The
  phrase is part of the commit body, not the header, so the grep can
  run against the already-stripped body instead, letting both steps
  share one commit_body call.

* t3900-i18n-commit.sh pipes the stripped body into "iconv" to test
  re-encoding. Piping commit_body's output into "iconv" would reintroduce
  an exit-code hole one line after removing it elsewhere, so this site
  writes the body to a file first and reads that, keeping the &&-chain
  intact.

Some greps for sed -e "1,/^\*$/d" left unconverted, as they are not extracting a commit's message body:

* t9001-send-email.sh strips mail headers from a message file, not a
  commit object.
* t1450-fsck.sh strips the header off a hand-built commit object while
  constructing a malformed one for fsck to reject.
* t4014-format-patch.sh runs the same sed address on a ".patch" file,
  with an additional expression.

All converted files pass in full, and a deliberately failing
"git cat-file" now fails a converted test that previously passed.

Signed-off-by: Shlok Kulshreshtha <diy2903@gmail.com>
---
 t/t3405-rebase-malformed.sh               |  8 +--
 t/t3408-rebase-multi-line.sh              |  4 +-
 t/t3434-rebase-i18n.sh                    |  3 +-
 t/t3900-i18n-commit.sh                    |  4 +-
 t/t4150-am.sh                             |  8 +--
 t/t7500-commit-template-squash-signoff.sh |  4 +-
 t/t7501-commit-basic-functionality.sh     | 21 +++----
 t/t7502-commit-porcelain.sh               | 77 ++++++++---------------
 t/t7600-merge.sh                          | 14 ++---
 t/t7604-merge-custom-message.sh           | 18 ++----
 t/t7614-merge-signoff.sh                  |  9 +--
 11 files changed, 62 insertions(+), 108 deletions(-)

diff --git a/t/t3405-rebase-malformed.sh b/t/t3405-rebase-malformed.sh
index 2524331861..271195fc11 100755
--- a/t/t3405-rebase-malformed.sh
+++ b/t/t3405-rebase-malformed.sh
@@ -37,7 +37,7 @@ test_expect_success setup '
 	test_tick &&
 	git commit -F F &&
 
-	git cat-file commit HEAD | sed -e "1,/^\$/d" >F0 &&
+	commit_body HEAD >F0 &&
 
 	git checkout diff-in-message &&
 	echo "commit log message containing a diff" >G &&
@@ -48,7 +48,7 @@ test_expect_success setup '
 	test_tick &&
 	git commit -F G &&
 
-	git cat-file commit HEAD | sed -e "1,/^\$/d" >G0 &&
+	commit_body HEAD >G0 &&
 
 	git checkout empty-message-merge &&
 	echo file3 >file3 &&
@@ -66,7 +66,7 @@ test_expect_success setup '
 test_expect_success 'rebase commit with multi-line subject' '
 
 	git rebase main multi-line-subject &&
-	git cat-file commit HEAD | sed -e "1,/^\$/d" >F1 &&
+	commit_body HEAD >F1 &&
 
 	test_cmp F0 F1 &&
 	test_cmp F F0
@@ -74,7 +74,7 @@ test_expect_success 'rebase commit with multi-line subject' '
 
 test_expect_success 'rebase commit with diff in message' '
 	git rebase main diff-in-message &&
-	git cat-file commit HEAD | sed -e "1,/^$/d" >G1 &&
+	commit_body HEAD >G1 &&
 	test_cmp G0 G1 &&
 	test_cmp G G0
 '
diff --git a/t/t3408-rebase-multi-line.sh b/t/t3408-rebase-multi-line.sh
index cde3562e3a..2ab89e1a7d 100755
--- a/t/t3408-rebase-multi-line.sh
+++ b/t/t3408-rebase-multi-line.sh
@@ -50,8 +50,8 @@ test_expect_success rebase '
 
 	git checkout side &&
 	git rebase main &&
-	git cat-file commit HEAD | sed -e "1,/^\$/d" >actual &&
-	git cat-file commit side@{1} | sed -e "1,/^\$/d" >expect &&
+	commit_body HEAD >actual &&
+	commit_body side@{1} >expect &&
 	test_cmp expect actual
 
 '
diff --git a/t/t3434-rebase-i18n.sh b/t/t3434-rebase-i18n.sh
index 8c94fdffc4..0f93a239f8 100755
--- a/t/t3434-rebase-i18n.sh
+++ b/t/t3434-rebase-i18n.sh
@@ -27,8 +27,7 @@ fi
 
 compare_msg () {
 	iconv -f "$2" -t "$3" "$TEST_DIRECTORY/t3434/$1" >expect &&
-	git cat-file commit HEAD >raw &&
-	sed "1,/^$/d" raw >actual &&
+	commit_body HEAD >actual &&
 	test_cmp expect actual
 }
 
diff --git a/t/t3900-i18n-commit.sh b/t/t3900-i18n-commit.sh
index 3c930ec202..b3f03bcbd0 100755
--- a/t/t3900-i18n-commit.sh
+++ b/t/t3900-i18n-commit.sh
@@ -232,8 +232,8 @@ test_commit_autosquash_multi_encoding () {
 		git rev-list HEAD >actual &&
 		test_line_count = 3 actual &&
 		iconv -f $old -t UTF-8 "$TEST_DIRECTORY"/t3900/$msg >expect &&
-		git cat-file commit HEAD^ >raw &&
-		(sed "1,/^$/d" raw | iconv -f $new -t utf-8) >actual &&
+		commit_body HEAD^ >raw &&
+		iconv -f $new -t utf-8 <raw >actual &&
 		test_cmp expect actual
 	'
 }
diff --git a/t/t4150-am.sh b/t/t4150-am.sh
index 61c3ce9018..ee96223668 100755
--- a/t/t4150-am.sh
+++ b/t/t4150-am.sh
@@ -1018,7 +1018,7 @@ test_expect_success 'am -s unexpected trailer block' '
 	Signed-off-by: J C H <j@c.h>
 	EOF
 	git commit -F msg &&
-	git cat-file commit HEAD | sed -e "1,/^$/d" >original &&
+	commit_body HEAD >original &&
 	git format-patch --stdout -1 >patch &&
 
 	git reset --hard HEAD^ &&
@@ -1027,7 +1027,7 @@ test_expect_success 'am -s unexpected trailer block' '
 		cat original &&
 		echo "Signed-off-by: $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL>"
 	) >expect &&
-	git cat-file commit HEAD | sed -e "1,/^$/d" >actual &&
+	commit_body HEAD >actual &&
 	test_cmp expect actual &&
 
 	cat >msg <<-\EOF &&
@@ -1038,7 +1038,7 @@ test_expect_success 'am -s unexpected trailer block' '
 	EOF
 	git reset HEAD^ &&
 	git commit -F msg file &&
-	git cat-file commit HEAD | sed -e "1,/^$/d" >original &&
+	commit_body HEAD >original &&
 	git format-patch --stdout -1 >patch &&
 
 	git reset --hard HEAD^ &&
@@ -1049,7 +1049,7 @@ test_expect_success 'am -s unexpected trailer block' '
 		echo &&
 		echo "Signed-off-by: $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL>"
 	) >expect &&
-	git cat-file commit HEAD | sed -e "1,/^$/d" >actual &&
+	commit_body HEAD >actual &&
 	test_cmp expect actual
 '
 
diff --git a/t/t7500-commit-template-squash-signoff.sh b/t/t7500-commit-template-squash-signoff.sh
index 66aff8e097..5e782ad8d7 100755
--- a/t/t7500-commit-template-squash-signoff.sh
+++ b/t/t7500-commit-template-squash-signoff.sh
@@ -59,7 +59,7 @@ test_expect_success 'nonexistent template file in config should return error' '
 test_expect_success 'nonexistent optional template file in config' '
 	test_config commit.template ":(optional)$(pwd)"/notexist &&
 	GIT_EDITOR="echo hello >" git commit --allow-empty &&
-	git cat-file commit HEAD | sed -e "1,/^$/d" >actual &&
+	commit_body HEAD >actual &&
 	echo hello >expect &&
 	test_cmp expect actual
 '
@@ -204,7 +204,7 @@ EOF
 test_expect_success '--signoff' '
 	echo "yet another content *narf*" >> foo &&
 	echo "zort" | git commit -s -F - foo &&
-	git cat-file commit HEAD | sed "1,/^\$/d" > output &&
+	commit_body HEAD >output &&
 	test_cmp expect output
 '
 
diff --git a/t/t7501-commit-basic-functionality.sh b/t/t7501-commit-basic-functionality.sh
index 7794babe46..d0af38df20 100755
--- a/t/t7501-commit-basic-functionality.sh
+++ b/t/t7501-commit-basic-functionality.sh
@@ -491,8 +491,7 @@ test_expect_success 'sign off (1)' '
 	echo 1 >positive &&
 	git add positive &&
 	git commit -s -m "thank you" &&
-	git cat-file commit HEAD >commit &&
-	sed -e "1,/^\$/d" commit >actual &&
+	commit_body HEAD >actual &&
 	(
 		echo thank you &&
 		echo &&
@@ -511,8 +510,7 @@ test_expect_success 'sign off (2)' '
 	git commit -s -m "thank you
 
 $existing" &&
-	git cat-file commit HEAD >commit &&
-	sed -e "1,/^\$/d" commit >actual &&
+	commit_body HEAD >actual &&
 	(
 		echo thank you &&
 		echo &&
@@ -532,8 +530,7 @@ test_expect_success 'signoff gap' '
 	git commit -s -m "welcome
 
 $alt" &&
-	git cat-file commit HEAD >commit &&
-	sed -e "1,/^\$/d" commit >actual &&
+	commit_body HEAD >actual &&
 	(
 		echo welcome &&
 		echo &&
@@ -553,8 +550,7 @@ test_expect_success 'signoff gap 2' '
 
 We have now
 $alt" &&
-	git cat-file commit HEAD >commit &&
-	sed -e "1,/^\$/d" commit >actual &&
+	commit_body HEAD >actual &&
 	(
 		echo welcome &&
 		echo &&
@@ -575,8 +571,7 @@ test_expect_success 'signoff respects trailer config' '
 
 non-trailer line
 Myfooter: x" &&
-	git cat-file commit HEAD >commit &&
-	sed -e "1,/^\$/d" commit >actual &&
+	commit_body HEAD >actual &&
 	(
 		echo subject &&
 		echo &&
@@ -593,8 +588,7 @@ Myfooter: x" &&
 
 non-trailer line
 Myfooter: x" &&
-	git cat-file commit HEAD >commit &&
-	sed -e "1,/^\$/d" commit >actual &&
+	commit_body HEAD >actual &&
 	(
 		echo subject &&
 		echo &&
@@ -626,8 +620,7 @@ test_expect_success 'multiple -m' '
 	>negative &&
 	git add negative &&
 	git commit -m "one" -m "two" -m "three" &&
-	git cat-file commit HEAD >commit &&
-	sed -e "1,/^\$/d" commit >actual &&
+	commit_body HEAD >actual &&
 	(
 		echo one &&
 		echo &&
diff --git a/t/t7502-commit-porcelain.sh b/t/t7502-commit-porcelain.sh
index 62e3970e3f..2adfe70b3d 100755
--- a/t/t7502-commit-porcelain.sh
+++ b/t/t7502-commit-porcelain.sh
@@ -175,8 +175,7 @@ test_expect_success 'commit --trailer with "="' '
 	Reported-by: C3 E3
 	Mentored-by: C4 E4
 	EOF
-	git cat-file commit HEAD >commit.msg &&
-	sed -e "1,/^\$/d" commit.msg >actual &&
+	commit_body HEAD >actual &&
 	test_cmp expected actual
 '
 
@@ -195,8 +194,7 @@ test_expect_success 'commit --trailer with -c and "replace" as ifexists' '
 		commit --trailer "Mentored-by: C4 E4" \
 		 --trailer "Helped-by: C3 E3" \
 		--amend &&
-	git cat-file commit HEAD >commit.msg &&
-	sed -e "1,/^\$/d"  commit.msg >actual &&
+	commit_body HEAD >actual &&
 	test_cmp expected actual
 '
 
@@ -217,8 +215,7 @@ test_expect_success 'commit --trailer with -c and "add" as ifexists' '
 		commit --trailer "Reported-by: C3 E3" \
 		--trailer "Mentored-by: C4 E4" \
 		--amend &&
-	git cat-file commit HEAD >commit.msg &&
-	sed -e "1,/^\$/d"  commit.msg >actual &&
+	commit_body HEAD >actual &&
 	test_cmp expected actual
 '
 
@@ -238,8 +235,7 @@ test_expect_success 'commit --trailer with -c and "donothing" as ifexists' '
 		commit --trailer "Mentored-by: C5 E5" \
 		--trailer "Reviewed-by: C6 E6" \
 		--amend &&
-	git cat-file commit HEAD >commit.msg &&
-	sed -e "1,/^\$/d"  commit.msg >actual &&
+	commit_body HEAD >actual &&
 	test_cmp expected actual
 '
 
@@ -259,8 +255,7 @@ test_expect_success 'commit --trailer with -c and "addIfDifferent" as ifexists'
 		commit --trailer "Reported-by: C3 E3" \
 		--trailer "Mentored-by: C5 E5" \
 		--amend &&
-	git cat-file commit HEAD >commit.msg &&
-	sed -e "1,/^\$/d"  commit.msg >actual &&
+	commit_body HEAD >actual &&
 	test_cmp expected actual
 '
 
@@ -280,8 +275,7 @@ test_expect_success 'commit --trailer with -c and "addIfDifferentNeighbor" as if
 		commit --trailer "Mentored-by: C4 E4" \
 		--trailer "Reported-by: C3 E3" \
 		--amend &&
-	git cat-file commit HEAD >commit.msg &&
-	sed -e "1,/^\$/d"  commit.msg >actual &&
+	commit_body HEAD >actual &&
 	test_cmp expected actual
 '
 
@@ -302,8 +296,7 @@ test_expect_success 'commit --trailer with -c and "end" as where' '
 		commit --trailer "Reported-by: C3 E3" \
 		--trailer "Mentored-by: C4 E4" \
 		--amend &&
-	git cat-file commit HEAD >commit.msg &&
-	sed -e "1,/^\$/d" commit.msg >actual &&
+	commit_body HEAD >actual &&
 	test_cmp expected actual
 '
 
@@ -323,8 +316,7 @@ test_expect_success 'commit --trailer with -c and "start" as where' '
 		commit --trailer "Signed-off-by: C O Mitter <committer@example.com>" \
 		--trailer "Signed-off-by: C1 E1" \
 		--amend &&
-	git cat-file commit HEAD >commit.msg &&
-	sed -e "1,/^\$/d" commit.msg >actual &&
+	commit_body HEAD >actual &&
 	test_cmp expected actual
 '
 
@@ -344,8 +336,7 @@ test_expect_success 'commit --trailer with -c and "after" as where' '
 		commit --trailer "Mentored-by: C4 E4" \
 		--trailer "Mentored-by: C5 E5" \
 		--amend &&
-	git cat-file commit HEAD >commit.msg &&
-	sed -e "1,/^\$/d" commit.msg >actual &&
+	commit_body HEAD >actual &&
 	test_cmp expected actual
 '
 
@@ -366,8 +357,7 @@ test_expect_success 'commit --trailer with -c and "before" as where' '
 		commit --trailer "Mentored-by: C3 E3" \
 		--trailer "Mentored-by: C2 E2" \
 		--amend &&
-	git cat-file commit HEAD >commit.msg &&
-	sed -e "1,/^\$/d" commit.msg >actual &&
+	commit_body HEAD >actual &&
 	test_cmp expected actual
 '
 
@@ -387,8 +377,7 @@ test_expect_success 'commit --trailer with -c and "donothing" as ifmissing' '
 		commit --trailer "Helped-by: C5 E5" \
 		--trailer "Based-by: C6 E6" \
 		--amend &&
-	git cat-file commit HEAD >commit.msg &&
-	sed -e "1,/^\$/d" commit.msg >actual &&
+	commit_body HEAD >actual &&
 	test_cmp expected actual
 '
 
@@ -409,8 +398,7 @@ test_expect_success 'commit --trailer with -c and "add" as ifmissing' '
 		commit --trailer "Helped-by: C5 E5" \
 		--trailer "Based-by: C6 E6" \
 		--amend &&
-	git cat-file commit HEAD >commit.msg &&
-	sed -e "1,/^\$/d" commit.msg >actual &&
+	commit_body HEAD >actual &&
 	test_cmp expected actual
 '
 
@@ -424,8 +412,7 @@ test_expect_success 'commit --trailer with -c ack.key ' '
 	EOF
 	git -c trailer.ack.key="Acked-by" \
 		commit --trailer "ack = Peff" -m "hello" &&
-	git cat-file commit HEAD >commit.msg &&
-	sed -e "1,/^\$/d" commit.msg >actual &&
+	commit_body HEAD >actual &&
 	test_cmp expected actual
 '
 
@@ -440,8 +427,7 @@ test_expect_success 'commit --trailer with -c and ":=#" as separators' '
 	git -c trailer.separators=":=#" \
 		-c trailer.bug.key="Bug #" \
 		commit --trailer "bug = 42" -m "I hate bug" &&
-	git cat-file commit HEAD >commit.msg &&
-	sed -e "1,/^\$/d" commit.msg >actual &&
+	commit_body HEAD >actual &&
 	test_cmp expected actual
 '
 
@@ -461,8 +447,7 @@ test_expect_success 'commit --trailer with -c and command' '
 		-c trailer.report.command="NAME=\"\$ARG\"; test -n \"\$NAME\" && \
 		git log --author=\"\$NAME\" -1 --format=\"format:%aN <%aE>\" || true" \
 		commit --trailer "report = author" --amend &&
-	git cat-file commit HEAD >commit.msg &&
-	sed -e "1,/^\$/d" commit.msg >actual &&
+	commit_body HEAD >actual &&
 	test_cmp expected actual
 '
 
@@ -480,8 +465,7 @@ test_expect_success 'commit --trailer not confused by --- separator' '
 		echo &&
 		echo "my-trailer: value"
 	} >expected &&
-	git cat-file commit HEAD >commit.msg &&
-	sed -e "1,/^\$/d" commit.msg >actual &&
+	commit_body HEAD >actual &&
 	test_cmp expected actual
 '
 
@@ -498,8 +482,7 @@ test_expect_success 'commit --trailer with --verbose' '
 		echo &&
 		echo "my-trailer: value"
 	} >expected &&
-	git cat-file commit HEAD >commit.msg &&
-	sed -e "1,/^\$/d" commit.msg >actual &&
+	commit_body HEAD >actual &&
 	test_cmp expected actual
 '
 
@@ -508,7 +491,7 @@ test_expect_success 'multiple -m' '
 	>negative &&
 	git add negative &&
 	git commit -m "one" -m "two" -m "three" &&
-	actual=$(git cat-file commit HEAD >tmp && sed -e "1,/^\$/d" tmp && rm tmp) &&
+	actual=$(commit_body HEAD) &&
 	expected=$(test_write_lines "one" "" "two" "" "three") &&
 	test "z$actual" = "z$expected"
 
@@ -545,8 +528,7 @@ test_expect_success 'cleanup commit messages (verbatim option,-t)' '
 
 	echo >>negative &&
 	git commit --cleanup=verbatim --no-status -t expect -a &&
-	git cat-file -p HEAD >raw &&
-	sed -e "1,/^\$/d" raw >actual &&
+	commit_body HEAD >actual &&
 	test_cmp expect actual
 
 '
@@ -555,8 +537,7 @@ test_expect_success 'cleanup commit messages (verbatim option,-F)' '
 
 	echo >>negative &&
 	git commit --cleanup=verbatim -F expect -a &&
-	git cat-file -p HEAD >raw &&
-	sed -e "1,/^\$/d" raw >actual &&
+	commit_body HEAD >actual &&
 	test_cmp expect actual
 
 '
@@ -565,8 +546,7 @@ test_expect_success 'cleanup commit messages (verbatim option,-m)' '
 
 	echo >>negative &&
 	git commit --cleanup=verbatim -m "$mesg_with_comment_and_newlines" -a &&
-	git cat-file -p HEAD >raw &&
-	sed -e "1,/^\$/d" raw >actual &&
+	commit_body HEAD >actual &&
 	test_cmp expect actual
 
 '
@@ -577,8 +557,7 @@ test_expect_success 'cleanup commit messages (whitespace option,-F)' '
 	test_write_lines "" "# text" "" >text &&
 	echo "# text" >expect &&
 	git commit --cleanup=whitespace -F text -a &&
-	git cat-file -p HEAD >raw &&
-	sed -e "1,/^\$/d" raw >actual &&
+	commit_body HEAD >actual &&
 	test_cmp expect actual
 
 '
@@ -605,8 +584,7 @@ test_expect_success 'cleanup commit messages (scissors option,-F,-e)' '
 	# to be kept, too
 	EOF
 	git commit --cleanup=scissors -e -F text -a &&
-	git cat-file -p HEAD >raw &&
-	sed -e "1,/^\$/d" raw >actual &&
+	commit_body HEAD >actual &&
 	test_cmp expect actual
 '
 
@@ -618,8 +596,7 @@ test_expect_success 'cleanup commit messages (scissors option,-F,-e, scissors on
 	to be removed
 	EOF
 	git commit --cleanup=scissors -e -F text -a --allow-empty-message &&
-	git cat-file -p HEAD >raw &&
-	sed -e "1,/^\$/d" raw >actual &&
+	commit_body HEAD >actual &&
 	test_must_be_empty actual
 '
 
@@ -629,8 +606,7 @@ test_expect_success 'cleanup commit messages (strip option,-F)' '
 	test_write_lines "" "# text" "sample" "" >text &&
 	echo sample >expect &&
 	git commit --cleanup=strip -F text -a &&
-	git cat-file -p HEAD >raw &&
-	sed -e "1,/^\$/d" raw >actual &&
+	commit_body HEAD >actual &&
 	test_cmp expect actual
 
 '
@@ -849,8 +825,7 @@ test_expect_success 'A single-liner subject with a token plus colon is not a foo
 
 	git reset --hard &&
 	git commit -s -m "hello: kitty" --allow-empty &&
-	git cat-file commit HEAD >raw &&
-	sed -e "1,/^$/d" raw >actual &&
+	commit_body HEAD >actual &&
 	test_line_count = 3 actual
 
 '
diff --git a/t/t7600-merge.sh b/t/t7600-merge.sh
index 7f2a1db16d..64cb83284c 100755
--- a/t/t7600-merge.sh
+++ b/t/t7600-merge.sh
@@ -332,8 +332,7 @@ test_expect_success 'merge --squash c3 with c7' '
 	# Conflicts:
 	#	file
 	EOF
-	git cat-file commit HEAD >raw &&
-	sed -e "1,/^$/d" raw >actual &&
+	commit_body HEAD >actual &&
 	test_cmp expect actual
 '
 
@@ -363,8 +362,7 @@ test_expect_success 'merge c3 with c7 with commit.cleanup = scissors' '
 	# Conflicts:
 	#	file
 	EOF
-	git cat-file commit HEAD >raw &&
-	sed -e "1,/^$/d" raw >actual &&
+	commit_body HEAD >actual &&
 	test_cmp expect actual
 '
 
@@ -387,8 +385,7 @@ test_expect_success 'merge c3 with c7 with --squash commit.cleanup = scissors' '
 	# Conflicts:
 	#	file
 	EOF
-	git cat-file commit HEAD >raw &&
-	sed -e "1,/^$/d" raw >actual &&
+	commit_body HEAD >actual &&
 	test_cmp expect actual
 '
 
@@ -989,9 +986,8 @@ test_expect_success 'merge --no-ff --edit' '
 	git reset --hard c0 &&
 	EDITOR=./editor git merge --no-ff --edit c1 &&
 	verify_parents $c0 $c1 &&
-	git cat-file commit HEAD >raw &&
-	test_grep "work done on the side branch" raw &&
-	sed "1,/^$/d" >actual raw &&
+	commit_body HEAD >actual &&
+	test_grep "work done on the side branch" actual &&
 	test_cmp expected actual
 '
 
diff --git a/t/t7604-merge-custom-message.sh b/t/t7604-merge-custom-message.sh
index cd4f9607dc..3a7d1ae858 100755
--- a/t/t7604-merge-custom-message.sh
+++ b/t/t7604-merge-custom-message.sh
@@ -36,16 +36,14 @@ test_expect_success 'setup' '
 test_expect_success 'merge c2 with a custom message' '
 	git reset --hard c1 &&
 	git merge -m "$(cat exp.subject)" c2 &&
-	git cat-file commit HEAD >raw &&
-	sed -e "1,/^$/d" raw >actual &&
+	commit_body HEAD >actual &&
 	test_cmp exp.subject actual
 '
 
 test_expect_success 'merge --log appends to custom message' '
 	git reset --hard c1 &&
 	git merge --log -m "$(cat exp.subject)" c2 &&
-	git cat-file commit HEAD >raw &&
-	sed -e "1,/^$/d" raw >actual &&
+	commit_body HEAD >actual &&
 	test_cmp exp.log actual
 '
 
@@ -61,8 +59,7 @@ test_expect_success 'prepare file with comment line and trailing newlines'  '
 test_expect_success 'cleanup commit messages (verbatim option)' '
 	git reset --hard c1 &&
 	git merge --cleanup=verbatim -F expect c2 &&
-	git cat-file commit HEAD >raw &&
-	sed -e "1,/^$/d" raw >actual &&
+	commit_body HEAD >actual &&
 	test_cmp expect actual
 '
 
@@ -71,8 +68,7 @@ test_expect_success 'cleanup commit messages (whitespace option)' '
 	test_write_lines "" "# text" "" >text &&
 	echo "# text" >expect &&
 	git merge --cleanup=whitespace -F text c2 &&
-	git cat-file commit HEAD >raw &&
-	sed -e "1,/^$/d" raw >actual &&
+	commit_body HEAD >actual &&
 	test_cmp expect actual
 '
 
@@ -97,8 +93,7 @@ test_expect_success 'cleanup merge messages (scissors option)' '
 	# to be kept, too
 	EOF
 	git merge --cleanup=scissors -e -F text c2 &&
-	git cat-file commit HEAD >raw &&
-	sed -e "1,/^$/d" raw >actual &&
+	commit_body HEAD >actual &&
 	test_cmp expect actual
 '
 
@@ -107,8 +102,7 @@ test_expect_success 'cleanup commit messages (strip option)' '
 	test_write_lines "" "# text" "sample" "" >text &&
 	echo sample >expect &&
 	git merge --cleanup=strip -F text c2 &&
-	git cat-file commit HEAD >raw &&
-	sed -e "1,/^$/d" raw >actual &&
+	commit_body HEAD >actual &&
 	test_cmp expect actual
 '
 
diff --git a/t/t7614-merge-signoff.sh b/t/t7614-merge-signoff.sh
index e58bf07b7a..b078eaf8a3 100755
--- a/t/t7614-merge-signoff.sh
+++ b/t/t7614-merge-signoff.sh
@@ -45,8 +45,7 @@ test_expect_success 'git merge --signoff adds a sign-off line' '
 	test_commit main-branch-2 file2 2 &&
 	git checkout other-branch &&
 	git merge main --signoff --no-edit &&
-	git cat-file commit HEAD >commit &&
-	sed -e "1,/^\$/d" commit >actual &&
+	commit_body HEAD >actual &&
 	test_cmp expected-signed actual
 '
 
@@ -56,8 +55,7 @@ test_expect_success 'git merge does not add a sign-off line' '
 	test_commit main-branch-3 file3 3 &&
 	git checkout other-branch &&
 	git merge main --no-edit &&
-	git cat-file commit HEAD >commit &&
-	sed -e "1,/^\$/d" commit >actual &&
+	commit_body HEAD >actual &&
 	test_cmp expected-unsigned actual
 '
 
@@ -67,8 +65,7 @@ test_expect_success 'git merge --no-signoff flag cancels --signoff flag' '
 	test_commit main-branch-4 file4 4 &&
 	git checkout other-branch &&
 	git merge main --no-edit --signoff --no-signoff &&
-	git cat-file commit HEAD >commit &&
-	sed -e "1,/^\$/d" commit >actual &&
+	commit_body HEAD >actual &&
 	test_cmp expected-unsigned actual
 '
 
-- 
2.52.0