✅ test: useOnlineStatus 테스트 코드 추가

Author: suhyeoonn

src/hooks/useOnlineStatus.test.ts

@@ -0,0 +1,82 @@
+import { act, renderHook } from '@testing-library/react';
+import useOnlineStatus from './useOnlineStatus';
+
+let windowSpy: jest.SpyInstance;
+let onlineCallback: jest.Mock;
+let offlineCallback: jest.Mock;
+
+describe('useOnlineStatus', () => {
+  beforeEach(() => {
+    windowSpy = jest.spyOn(global, 'window', 'get');
+    onlineCallback = jest.fn();
+    offlineCallback = jest.fn();
+  });
+
+  afterEach(() => {
+    windowSpy.mockRestore();
+  });
+
+  test('온라인 상태라면 isOnline은 true이다.', () => {
+    jest.spyOn(navigator, 'onLine', 'get').mockReturnValueOnce(true);
+
+    const { result } = renderHook(() => useOnlineStatus());
+
+    expect(result.current.isOnline).toBe(true);
+  });
+
+  test('오프라인 상태에서 isOnline은 false이다.', () => {
+    jest.spyOn(navigator, 'onLine', 'get').mockReturnValueOnce(false);
+
+    const { result } = renderHook(() => useOnlineStatus());
+
+    expect(result.current.isOnline).toBe(false);
+  });
+
+  test('네트워크 상태가 변경되면 isOnline 상태가 갱신된다.', () => {
+    const { result } = renderHook(() => useOnlineStatus());
+
+    act(() => {
+      window.dispatchEvent(new Event('offline'));
+    });
+
+    expect(result.current.isOnline).toBe(false);
+
+    act(() => {
+      window.dispatchEvent(new Event('online'));
+    });
+
+    expect(result.current.isOnline).toBe(true);
+  });
+
+  test('콜백 함수가 호출되는지 확인', () => {
+    renderHook(() => useOnlineStatus({ onlineCallback, offlineCallback }));
+    act(() => {
+      window.dispatchEvent(new Event('offline'));
+    });
+
+    expect(offlineCallback).toHaveBeenCalledTimes(1);
+
+    act(() => {
+      window.dispatchEvent(new Event('online'));
+    });
+    expect(onlineCallback).toHaveBeenCalledTimes(1);
+  });
+
+  test('언마운트 시 이벤트 리스너가 제거된다.', () => {
+    const { unmount } = renderHook(() =>
+      useOnlineStatus({ onlineCallback, offlineCallback })
+    );
+
+    unmount();
+
+    act(() => {
+      window.dispatchEvent(new Event('offline'));
+    });
+    expect(offlineCallback).toHaveBeenCalledTimes(0);
+
+    act(() => {
+      window.dispatchEvent(new Event('online'));
+    });
+    expect(onlineCallback).toHaveBeenCalledTimes(0);
+  });
+});