diff --git a/tests/k6/create_repos.bash b/tests/k6/create_repos.bash
index d2e955a..83ce9fb 100755
--- a/tests/k6/create_repos.bash
+++ b/tests/k6/create_repos.bash
@@ -64,5 +64,23 @@ git ${GIT_FLAGS[@]} -C foo commit \
 	-m "Create Go application entrypoint" \
 	--date "2026-06-06T12:01:00+09:00"
 
+echo "first write, start" > foo/diff-whole.txt
+for i in $(seq 1 9999); do
+	echo "first write, #$i" >> foo/diff-whole.txt
+done
+git ${GIT_FLAGS[@]} -C foo add diff-whole.txt
+git ${GIT_FLAGS[@]} -C foo commit \
+	-m "diff-whole.txt, first write" \
+	--date "2026-06-06T12:01:00+09:00"
+
+echo "second write, start" > foo/diff-whole.txt
+for i in $(seq 1 9999); do
+	echo "second write, #$i" >> foo/diff-whole.txt
+done
+git ${GIT_FLAGS[@]} -C foo add diff-whole.txt
+git ${GIT_FLAGS[@]} -C foo commit \
+	-m "diff-whole.txt, second write" \
+	--date "2026-06-06T12:02:00+09:00"
+
 git clone --bare foo foo.git
 rm -rf foo
diff --git a/tests/k6/spam_repo_commit_large_diff.js b/tests/k6/spam_repo_commit_large_diff.js
new file mode 100644
index 0000000..19091c6
--- /dev/null
+++ b/tests/k6/spam_repo_commit_large_diff.js
@@ -0,0 +1,12 @@
+// Copyright 2026 Shota FUJI <pockawoooh@gmail.com>
+// SPDX-License-Identifier: MIT
+
+import http from "k6/http";
+
+export const options = {
+	iterations: 10,
+};
+
+export default function() {
+	http.get("http://localhost:8080/foo.git/commit/0aacdb88132758978fada845ee2438aa1db094fd");
+}