[PATCH v3 1/2] t5403:introduce check_post_checkout helper function

[Deveshi Dwivedi <deveshigurgaon@gmail.com>]

The test file repeatedly uses the same four-line pattern to validate
post-checkout hook arguments: read the args file, then test each of
the three values individually.

Introduce a check_post_checkout helper function that encapsulates this
pattern. This patch does not change test behavior; it prepares the
code for improvement in the next step.

Additionally, the 'post-checkout hook is triggered by clone' test is
improved to validate the hook arguments (old ref, new ref, and flag)
rather than just checking that the hook file was created.

Signed-off-by: Deveshi Dwivedi <deveshigurgaon@gmail.com>
---
 t/t5403-post-checkout-hook.sh | 49 ++++++++++++++++++++---------------
 1 file changed, 28 insertions(+), 21 deletions(-)

diff --git a/t/t5403-post-checkout-hook.sh b/t/t5403-post-checkout-hook.sh
index 1462e3365b..7bdea25107 100755
--- a/t/t5403-post-checkout-hook.sh
+++ b/t/t5403-post-checkout-hook.sh
@@ -9,6 +9,17 @@ export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 
 . ./test-lib.sh
 
+# Usage: check_post_checkout <file> <old-ref> <new-ref> <flag>
+#
+# Verify that the post-checkout hook arguments in <file> match the expected
+# values: <old-ref> for the previous HEAD, <new-ref> for the new HEAD, and
+# <flag> indicating whether this was a branch checkout (1) or file checkout (0).
+check_post_checkout () {
+	test "$#" = 4 || BUG "check_post_checkout takes 4 args"
+	read old new flag <"$1" &&
+	test "$old" = "$2" && test "$new" = "$3" && test "$flag" = "$4"
+}
+
 test_expect_success setup '
 	test_hook --setup post-checkout <<-\EOF &&
 	echo "$@" >.git/post-checkout.args
@@ -23,29 +34,30 @@ test_expect_success setup '
 test_expect_success 'post-checkout receives the right arguments with HEAD unchanged ' '
 	test_when_finished "rm -f .git/post-checkout.args" &&
 	git checkout main &&
-	read old new flag <.git/post-checkout.args &&
-	test $old = $new && test $flag = 1
+	check_post_checkout .git/post-checkout.args \
+		"$(git rev-parse HEAD)" "$(git rev-parse HEAD)" 1
 '
 
 test_expect_success 'post-checkout args are correct with git checkout -b ' '
 	test_when_finished "rm -f .git/post-checkout.args" &&
 	git checkout -b new1 &&
-	read old new flag <.git/post-checkout.args &&
-	test $old = $new && test $flag = 1
+	check_post_checkout .git/post-checkout.args \
+		"$(git rev-parse HEAD)" "$(git rev-parse HEAD)" 1
 '
 
 test_expect_success 'post-checkout receives the right args with HEAD changed ' '
 	test_when_finished "rm -f .git/post-checkout.args" &&
+	old=$(git rev-parse HEAD) &&
 	git checkout two &&
-	read old new flag <.git/post-checkout.args &&
-	test $old != $new && test $flag = 1
+	check_post_checkout .git/post-checkout.args \
+		"$old" "$(git rev-parse HEAD)" 1
 '
 
 test_expect_success 'post-checkout receives the right args when not switching branches ' '
 	test_when_finished "rm -f .git/post-checkout.args" &&
 	git checkout main -- three.t &&
-	read old new flag <.git/post-checkout.args &&
-	test $old = $new && test $flag = 0
+	check_post_checkout .git/post-checkout.args \
+		"$(git rev-parse HEAD)" "$(git rev-parse HEAD)" 0
 '
 
 test_rebase () {
@@ -55,10 +67,8 @@ test_rebase () {
 		git checkout -B rebase-test main &&
 		rm -f .git/post-checkout.args &&
 		git rebase $args rebase-on-me &&
-		read old new flag <.git/post-checkout.args &&
-		test_cmp_rev main $old &&
-		test_cmp_rev rebase-on-me $new &&
-		test $flag = 1
+		check_post_checkout .git/post-checkout.args \
+			"$(git rev-parse main)" "$(git rev-parse rebase-on-me)" 1
 	'
 
 	test_expect_success "post-checkout is triggered on rebase $args with fast-forward" '
@@ -66,10 +76,8 @@ test_rebase () {
 		git checkout -B ff-rebase-test rebase-on-me^ &&
 		rm -f .git/post-checkout.args &&
 		git rebase $args rebase-on-me &&
-		read old new flag <.git/post-checkout.args &&
-		test_cmp_rev rebase-on-me^ $old &&
-		test_cmp_rev rebase-on-me $new &&
-		test $flag = 1
+		check_post_checkout .git/post-checkout.args \
+			"$(git rev-parse rebase-on-me^)" "$(git rev-parse rebase-on-me)" 1
 	'
 
 	test_expect_success "rebase $args fast-forward branch checkout runs post-checkout hook" '
@@ -79,10 +87,8 @@ test_rebase () {
 		git checkout two  &&
 		rm -f .git/post-checkout.args &&
 		git rebase $args HEAD rebase-fast-forward  &&
-		read old new flag <.git/post-checkout.args &&
-		test_cmp_rev two $old &&
-		test_cmp_rev three $new &&
-		test $flag = 1
+		check_post_checkout .git/post-checkout.args \
+			"$(git rev-parse two)" "$(git rev-parse three)" 1
 	'
 
 	test_expect_success "rebase $args checkout does not remove untracked files" '
@@ -109,7 +115,8 @@ test_expect_success 'post-checkout hook is triggered by clone' '
 	echo "$@" >"$GIT_DIR/post-checkout.args"
 	EOF
 	git clone --template=templates . clone3 &&
-	test_path_is_file clone3/.git/post-checkout.args
+	check_post_checkout clone3/.git/post-checkout.args \
+		"$(test_oid zero)" "$(git -C clone3 rev-parse HEAD)" 1
 '
 
 test_done
-- 
2.52.0.230.gd8af7cadaa