refactor: added some tests

src/course-unit/xblock-container-iframe/tests/hooks.test.tsx

@@ -51,6 +51,32 @@ describe('useIFrameBehavior', () => {
     expect(result.current.hasLoaded).toBe(false);
   });
 
+  it('scrolls to previous position on video fullscreen exit', () => {
+    const mockWindowTopOffset = 100;
+
+    (useKeyedState as jest.Mock).mockImplementation((key) => {
+      if (key === stateKeys.windowTopOffset) {
+        return [mockWindowTopOffset, setWindowTopOffset];
+      }
+      return [null, jest.fn()];
+    });
+
+    renderHook(() => useIFrameBehavior({ id, iframeUrl }));
+
+    const message = {
+      data: {
+        type: messageTypes.videoFullScreen,
+        payload: { open: false },
+      },
+    };
+
+    act(() => {
+      window.dispatchEvent(new MessageEvent('message', message));
+    });
+
+    expect(window.scrollTo).toHaveBeenCalledWith(0, mockWindowTopOffset);
+  });
+
   it('handles resize message correctly', () => {
     renderHook(() => useIFrameBehavior({ id, iframeUrl }));