diff --git a/packages/frontend/src/scripts/check-word-mute.ts b/packages/frontend/src/scripts/check-word-mute.ts
index 94916aacda..9ddbc5362e 100644
--- a/packages/frontend/src/scripts/check-word-mute.ts
+++ b/packages/frontend/src/scripts/check-word-mute.ts
@@ -18,7 +18,7 @@ type GlobalMisskeyWordMute = {
 	hard: WordMuteInfo;
 };
 
-function createWordMuteInfo(mutedWords: Array<string | string[]>) : WordMuteInfo {
+export function createWordMuteInfo(mutedWords: Array<string | string[]>) : WordMuteInfo {
 	if (mutedWords.length <= 0) return false;
 	const normalTexts: string[] = [];
 	const andTexts: string[][] = [];
diff --git a/packages/frontend/test/mocks.ts b/packages/frontend/test/mocks.ts
new file mode 100644
index 0000000000..fca3080880
--- /dev/null
+++ b/packages/frontend/test/mocks.ts
@@ -0,0 +1,44 @@
+/*
+ * SPDX-FileCopyrightText: syuilo and misskey-project
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+import type * as Misskey from 'misskey-js';
+import { vi } from 'vitest';
+
+export const UserLiteMock = vi.fn(() => {
+	return {
+		id: 'xxxxxxxx',
+		username: 'ai',
+		host: null,
+		name: '藍',
+		avatarUrl: null,
+		avatarBlurhash: null,
+		avatarDecorations: [],
+		emojis: {},
+		onlineStatus:	'online',
+	} as Misskey.entities.UserLite;
+});
+
+export const NoteMock = vi.fn((options?: {
+	text?: string,
+	cw?: string,
+}) => {
+	const user = new UserLiteMock();
+	return {
+		id: 'xxxxxxxx',
+		// 2025/01/01 00:00:00 UTC on Unix time
+		createdAt: '1767225600000',
+		text: options?.text ?? 'Hello, Misskey!',
+		cw: options?.cw,
+		userId: user.id,
+		user: user,
+		visibility: 'public',
+		reactionAcceptance: null,
+		reactionEmojis: {},
+		reactions: {},
+		reactionCount: 0,
+		renoteCount: 0,
+		repliesCount: 0,
+	} as Misskey.entities.Note;
+});
diff --git a/packages/frontend/test/word-mute.test.ts b/packages/frontend/test/word-mute.test.ts
new file mode 100644
index 0000000000..f0c65bb1a4
--- /dev/null
+++ b/packages/frontend/test/word-mute.test.ts
@@ -0,0 +1,76 @@
+/*
+ * SPDX-FileCopyrightText: syuilo and misskey-project
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+import { describe, test, assert } from 'vitest';
+import { createWordMuteInfo, checkWordMute } from '@/scripts/check-word-mute.js';
+import { NoteMock } from './mocks.js';
+
+type TestCases = {
+	text: string,
+	cw?: string,
+	mutedWords: Array<string | string[]>,
+	result: false | Array<string | string[]>,
+}
+
+describe('check-word-mute', () => {
+	const cases:Array<TestCases> = [
+		{
+			text: 'Hello, Misskey!',
+			mutedWords: ['Misskey'],
+			result: [['Misskey']],
+		},
+		// cw
+		{
+			text: 'Hello, Misskey!',
+			cw: 'ai',
+			mutedWords: ['ai'],
+			result: [['ai']],
+		},
+		// nothing
+		{
+			text: 'Hello, Misskey!',
+			mutedWords: [],
+			result: false,
+		},
+		// surrogate pair
+		{
+			text: '𠮟る',
+			mutedWords: ['𠮟'],
+			result: [['𠮟']],
+		},
+		// grapheme cluster
+		{
+			text: '👩‍❤️‍👨',
+			mutedWords: ['👩'],
+			result: false,
+		},
+		// regex
+		{
+			text: 'Hello, Misskey!',
+			mutedWords: ['/M[isk]*ey/'],
+			result: ['/M[isk]*ey/'],
+		},
+		// multi wordas
+		{
+			text: 'Hello, Misskey!',
+			mutedWords: [['Hello', 'Misskey'], ['Mi']],
+			result: [['Mi'],['Hello', 'Misskey']],
+		},
+	]
+
+	cases.forEach((c) => {
+		test(`text: ${c.text}, cw: ${c.cw}, mutedWords: ${c.mutedWords}` , async () => {
+			// initWordMuteInfoが実行されないので代わりにここで初期化
+			(globalThis as any)._misskeyWordMute = {
+				soft: createWordMuteInfo(c.mutedWords),
+				hard: createWordMuteInfo([]),
+			}
+
+			const note = NoteMock({ text: c.text, cw: c.cw });
+			const result = checkWordMute(note, null, 'soft');
+			assert.deepEqual(result, c.result);
+		});
+	});
+});