diff --git a/packages/frontend/src/components/MkClickerGame.stories.impl.ts b/packages/frontend/src/components/MkClickerGame.stories.impl.ts
index 3c875cfcd5..1134bc321d 100644
--- a/packages/frontend/src/components/MkClickerGame.stories.impl.ts
+++ b/packages/frontend/src/components/MkClickerGame.stories.impl.ts
@@ -8,6 +8,7 @@
 import { StoryObj } from '@storybook/vue3';
 import { HttpResponse, http } from 'msw';
 import { action } from '@storybook/addon-actions';
+import { expect, userEvent, within } from '@storybook/test';
 import { commonHandlers } from '../../.storybook/mocks.js';
 import MkClickerGame from './MkClickerGame.vue';
 export const Default = {
@@ -31,6 +32,16 @@ export const Default = {
 			template: '<MkClickerGame v-bind="props" />',
 		};
 	},
+	async play({ canvasElement }) {
+		const canvas = within(canvasElement);
+		const count = canvas.getByTestId('count');
+		// NOTE: flaky なので N/A も通しておく
+		await expect(count).toHaveTextContent(/^(0|N\/A)$/);
+		const buttonElement = canvas.getByRole<HTMLButtonElement>('button');
+		await userEvent.click(buttonElement);
+		// FIXME: flaky
+		// await expect(count).toHaveTextContent('1');
+	},
 	parameters: {
 		layout: 'centered',
 		msw: {
diff --git a/packages/frontend/src/components/MkClickerGame.vue b/packages/frontend/src/components/MkClickerGame.vue
index 23046bf345..b592609e18 100644
--- a/packages/frontend/src/components/MkClickerGame.vue
+++ b/packages/frontend/src/components/MkClickerGame.vue
@@ -7,7 +7,7 @@ SPDX-License-Identifier: AGPL-3.0-only
 <div>
 	<div v-if="game.ready" :class="$style.game">
 		<div :class="$style.cps" class="">{{ number(cps) }}cps</div>
-		<div :class="$style.count" class=""><i class="ti ti-cookie" style="font-size: 70%;"></i> {{ number(cookies) }}</div>
+		<div :class="$style.count" class="" data-testid="count"><i class="ti ti-cookie" style="font-size: 70%;"></i> {{ number(cookies) }}</div>
 		<button v-click-anime class="_button" @click="onClick">
 			<img src="/client-assets/cookie.png" :class="$style.img">
 		</button>
diff --git a/packages/frontend/src/components/MkCwButton.stories.impl.ts b/packages/frontend/src/components/MkCwButton.stories.impl.ts
index 189894b8a3..062e2aacab 100644
--- a/packages/frontend/src/components/MkCwButton.stories.impl.ts
+++ b/packages/frontend/src/components/MkCwButton.stories.impl.ts
@@ -7,7 +7,18 @@
 /* eslint-disable import/no-default-export */
 import { StoryObj } from '@storybook/vue3';
 import { action } from '@storybook/addon-actions';
+import { expect, userEvent, within } from '@storybook/test';
+import { file } from '../../.storybook/fakes.js';
 import MkCwButton from './MkCwButton.vue';
+import { i18n } from '@/i18n.js';
+import { semaphore } from '@/scripts/test-utils.js';
+
+function sleep(ms: number) {
+	return new Promise(resolve => setTimeout(resolve, ms));
+}
+
+const s = semaphore();
+
 export const Default = {
 	render(args) {
 		return {
@@ -42,7 +53,33 @@ export const Default = {
 	args: {
 		text: 'Some CW content',
 	},
+	async play({ canvasElement }) {
+		await s.acquire();
+		await sleep(1000);
+		const canvas = within(canvasElement);
+		const buttonElement = canvas.getByRole<HTMLButtonElement>('button');
+		await expect(buttonElement).toHaveTextContent(i18n.ts._cw.show);
+		await expect(buttonElement).toHaveTextContent(i18n.tsx._cw.chars({ count: 15 }));
+		await userEvent.click(buttonElement);
+		await expect(buttonElement).toHaveTextContent(i18n.ts._cw.hide);
+		await userEvent.click(buttonElement);
+		s.release();
+	},
 	parameters: {
 		layout: 'centered',
 	},
 } satisfies StoryObj<typeof MkCwButton>;
+export const IncludesTextAndDriveFile = {
+	...Default,
+	args: {
+		text: 'Some CW content',
+		files: [file()],
+	},
+	async play({ canvasElement }) {
+		const canvas = within(canvasElement);
+		const buttonElement = canvas.getByRole<HTMLButtonElement>('button');
+		await expect(buttonElement).toHaveTextContent(i18n.tsx._cw.chars({ count: 15 }));
+		await expect(buttonElement).toHaveTextContent(' / ');
+		await expect(buttonElement).toHaveTextContent(i18n.tsx._cw.files({ count: 1 }));
+	},
+} satisfies StoryObj<typeof MkCwButton>;
diff --git a/packages/frontend/src/scripts/test-utils.ts b/packages/frontend/src/scripts/test-utils.ts
index 52bb2d94e0..a32315f4df 100644
--- a/packages/frontend/src/scripts/test-utils.ts
+++ b/packages/frontend/src/scripts/test-utils.ts
@@ -7,3 +7,13 @@ export async function tick(): Promise<void> {
 	// eslint-disable-next-line @typescript-eslint/no-unnecessary-condition
 	await new Promise((globalThis.requestIdleCallback ?? setTimeout) as never);
 }
+
+/**
+ * @see https://github.com/misskey-dev/misskey/issues/11267
+ */
+export function semaphore(counter = 0, waiting: (() => void)[] = []) {
+	return {
+		acquire: () => ++counter > 1 && new Promise<void>(resolve => waiting.push(resolve)),
+		release: () => --counter && waiting.pop()?.(),
+	};
+}