Fix webview tests

webview-ui/src/setupTests.ts

@@ -1,5 +1,16 @@
-// jest-dom adds custom jest matchers for asserting on DOM nodes.
-// allows you to do things like:
-// expect(element).toHaveTextContent(/react/i)
-// learn more: https://github.com/testing-library/jest-dom
-import "@testing-library/jest-dom"
+import '@testing-library/jest-dom';
+
+// Mock window.matchMedia
+Object.defineProperty(window, 'matchMedia', {
+  writable: true,
+  value: jest.fn().mockImplementation(query => ({
+    matches: false,
+    media: query,
+    onchange: null,
+    addListener: jest.fn(), // Deprecated
+    removeListener: jest.fn(), // Deprecated
+    addEventListener: jest.fn(),
+    removeEventListener: jest.fn(),
+    dispatchEvent: jest.fn(),
+  })),
+});