diff --git a/apps/web/src/test/pages/editing-planner/components/TtsPanel.test.tsx b/apps/web/src/test/pages/editing-planner/components/TtsPanel.test.tsx
index c6989db77..5d0f8a28e 100644
--- a/apps/web/src/test/pages/editing-planner/components/TtsPanel.test.tsx
+++ b/apps/web/src/test/pages/editing-planner/components/TtsPanel.test.tsx
@@ -1,5 +1,5 @@
 import { afterEach, describe, expect, it, vi } from "vitest"
-import { render, cleanup } from "@testing-library/react"
+import { render, cleanup, act } from "@testing-library/react"
 import TtsPanel from "@/pages/editing-planner/components/TtsPanel"
 import { DEFAULT_TTS_CONFIG } from "@/pages/editing-planner/types"
 
@@ -16,17 +16,28 @@ const defaultProps = {
 }
 
 describe("TtsPanel", () => {
-  afterEach(() => {
+  afterEach(async () => {
+    // Flush pending React updates before cleanup to avoid
+    // "window is not defined" errors after jsdom teardown
+    await act(async () => {})
     cleanup()
   })
 
-  it("should render without crashing", () => {
-    const { container } = render(<TtsPanel {...defaultProps} />)
-    expect(container).toBeTruthy()
+  it("should render without crashing", async () => {
+    let container: HTMLElement
+    await act(async () => {
+      const result = render(<TtsPanel {...defaultProps} />)
+      container = result.container
+    })
+    expect(container!).toBeTruthy()
   })
 
-  it("should render when closed", () => {
-    const { container } = render(<TtsPanel {...defaultProps} open={false} />)
-    expect(container).toBeTruthy()
+  it("should render when closed", async () => {
+    let container: HTMLElement
+    await act(async () => {
+      const result = render(<TtsPanel {...defaultProps} open={false} />)
+      container = result.container
+    })
+    expect(container!).toBeTruthy()
   })
 })