test: add tests for useStatusPolling hook and Sidebar component

- 12 tests for useStatusPolling: WebSocket lifecycle, auth guards,
  message routing (status/scan_device_found), error resilience, cleanup
- 21 tests for Sidebar: render, collapse/expand, node stats, action
  callbacks, view navigation, scan trigger, settings panel toggle

frontend/src/hooks/__tests__/useStatusPolling.test.ts

@@ -0,0 +1,170 @@
+import { describe, it, expect, beforeEach, afterEach, vi } from 'vitest'
+import { renderHook } from '@testing-library/react'
+import { useStatusPolling } from '../useStatusPolling'
+import { useCanvasStore } from '@/stores/canvasStore'
+import { useAuthStore } from '@/stores/authStore'
+
+vi.mock('@/stores/canvasStore')
+vi.mock('@/stores/authStore')
+
+const mockUpdateNode = vi.fn()
+const mockNotifyScanDeviceFound = vi.fn()
+
+class MockWebSocket {
+  static instances: MockWebSocket[] = []
+  url: string
+  onopen: (() => void) | null = null
+  onmessage: ((e: { data: string }) => void) | null = null
+  onerror: ((e: unknown) => void) | null = null
+  send = vi.fn()
+  close = vi.fn()
+
+  constructor(url: string) {
+    this.url = url
+    MockWebSocket.instances.push(this)
+  }
+}
+
+describe('useStatusPolling', () => {
+  beforeEach(() => {
+    MockWebSocket.instances = []
+    vi.stubGlobal('WebSocket', MockWebSocket)
+
+    vi.mocked(useCanvasStore).mockReturnValue({
+      updateNode: mockUpdateNode,
+      notifyScanDeviceFound: mockNotifyScanDeviceFound,
+    } as ReturnType<typeof useCanvasStore>)
+
+    vi.mocked(useAuthStore).mockReturnValue({
+      isAuthenticated: true,
+      token: 'test-token',
+    } as ReturnType<typeof useAuthStore>)
+
+    Object.defineProperty(window, 'location', {
+      value: { protocol: 'http:', host: 'localhost:5173' },
+      writable: true,
+    })
+  })
+
+  afterEach(() => {
+    vi.restoreAllMocks()
+    mockUpdateNode.mockClear()
+    mockNotifyScanDeviceFound.mockClear()
+  })
+
+  it('does not open WebSocket when not authenticated', () => {
+    vi.mocked(useAuthStore).mockReturnValue({
+      isAuthenticated: false,
+      token: null,
+    } as ReturnType<typeof useAuthStore>)
+    renderHook(() => useStatusPolling())
+    expect(MockWebSocket.instances).toHaveLength(0)
+  })
+
+  it('does not open WebSocket when token is missing', () => {
+    vi.mocked(useAuthStore).mockReturnValue({
+      isAuthenticated: true,
+      token: null,
+    } as ReturnType<typeof useAuthStore>)
+    renderHook(() => useStatusPolling())
+    expect(MockWebSocket.instances).toHaveLength(0)
+  })
+
+  it('connects to correct ws:// URL', () => {
+    renderHook(() => useStatusPolling())
+    expect(MockWebSocket.instances).toHaveLength(1)
+    expect(MockWebSocket.instances[0].url).toBe('ws://localhost:5173/api/v1/status/ws/status')
+  })
+
+  it('uses wss:// when page is served over https', () => {
+    Object.defineProperty(window, 'location', {
+      value: { protocol: 'https:', host: 'mylab.local' },
+      writable: true,
+    })
+    renderHook(() => useStatusPolling())
+    expect(MockWebSocket.instances[0].url).toMatch(/^wss:\/\//)
+  })
+
+  it('sends token as first message on open', () => {
+    renderHook(() => useStatusPolling())
+    const ws = MockWebSocket.instances[0]
+    ws.onopen?.()
+    expect(ws.send).toHaveBeenCalledWith(JSON.stringify({ token: 'test-token' }))
+  })
+
+  it('calls updateNode with correct data on status message', () => {
+    renderHook(() => useStatusPolling())
+    const ws = MockWebSocket.instances[0]
+    ws.onmessage?.({
+      data: JSON.stringify({
+        node_id: 'node-1',
+        status: 'online',
+        checked_at: '2024-01-01T12:00:00Z',
+        response_time_ms: 42,
+      }),
+    })
+    expect(mockUpdateNode).toHaveBeenCalledWith('node-1', {
+      status: 'online',
+      response_time_ms: 42,
+      last_seen: '2024-01-01T12:00:00Z',
+    })
+  })
+
+  it('sets last_seen to undefined when status is offline', () => {
+    renderHook(() => useStatusPolling())
+    const ws = MockWebSocket.instances[0]
+    ws.onmessage?.({
+      data: JSON.stringify({
+        node_id: 'node-1',
+        status: 'offline',
+        checked_at: '2024-01-01T12:00:00Z',
+      }),
+    })
+    expect(mockUpdateNode).toHaveBeenCalledWith('node-1', {
+      status: 'offline',
+      response_time_ms: undefined,
+      last_seen: undefined,
+    })
+  })
+
+  it('sets response_time_ms to undefined when null in message', () => {
+    renderHook(() => useStatusPolling())
+    const ws = MockWebSocket.instances[0]
+    ws.onmessage?.({
+      data: JSON.stringify({ node_id: 'node-1', status: 'online', response_time_ms: null }),
+    })
+    expect(mockUpdateNode).toHaveBeenCalledWith(
+      'node-1',
+      expect.objectContaining({ response_time_ms: undefined }),
+    )
+  })
+
+  it('calls notifyScanDeviceFound on scan_device_found message', () => {
+    renderHook(() => useStatusPolling())
+    const ws = MockWebSocket.instances[0]
+    ws.onmessage?.({ data: JSON.stringify({ type: 'scan_device_found' }) })
+    expect(mockNotifyScanDeviceFound).toHaveBeenCalledOnce()
+    expect(mockUpdateNode).not.toHaveBeenCalled()
+  })
+
+  it('ignores malformed JSON without throwing', () => {
+    renderHook(() => useStatusPolling())
+    const ws = MockWebSocket.instances[0]
+    expect(() => ws.onmessage?.({ data: 'not-valid-json{{' })).not.toThrow()
+    expect(mockUpdateNode).not.toHaveBeenCalled()
+  })
+
+  it('ignores messages with no node_id or status', () => {
+    renderHook(() => useStatusPolling())
+    const ws = MockWebSocket.instances[0]
+    ws.onmessage?.({ data: JSON.stringify({ some: 'unknown-field' }) })
+    expect(mockUpdateNode).not.toHaveBeenCalled()
+  })
+
+  it('closes WebSocket on unmount', () => {
+    const { unmount } = renderHook(() => useStatusPolling())
+    const ws = MockWebSocket.instances[0]
+    unmount()
+    expect(ws.close).toHaveBeenCalledOnce()
+  })
+})