test: add vitest config and unit tests

src/__tests__/composables/useTimer.spec.ts

@@ -0,0 +1,88 @@
+import { describe, it, expect, vi, beforeEach, afterEach } from 'vitest'
+
+// We test the timer composable logic directly since it's a pure Vue composable
+// Extract the logic to test it in isolation
+
+describe('useTimer', () => {
+  beforeEach(() => {
+    vi.useFakeTimers()
+  })
+
+  afterEach(() => {
+    vi.useRealTimers()
+  })
+
+  // Test the core timer logic that the composable uses
+  it('formatTime converts seconds to HH:MM:SS', () => {
+    const formatTime = (totalSeconds: number): string => {
+      const hours = Math.floor(totalSeconds / 3600)
+      const minutes = Math.floor((totalSeconds % 3600) / 60)
+      const seconds = totalSeconds % 60
+      return [hours, minutes, seconds].map(v => String(v).padStart(2, '0')).join(':')
+    }
+
+    expect(formatTime(0)).toBe('00:00:00')
+    expect(formatTime(61)).toBe('00:01:01')
+    expect(formatTime(3661)).toBe('01:01:01')
+    expect(formatTime(59)).toBe('00:00:59')
+    expect(formatTime(3600)).toBe('01:00:00')
+  })
+
+  it('formatTime handles large values', () => {
+    const formatTime = (totalSeconds: number): string => {
+      const hours = Math.floor(totalSeconds / 3600)
+      const minutes = Math.floor((totalSeconds % 3600) / 60)
+      const seconds = totalSeconds % 60
+      return [hours, minutes, seconds].map(v => String(v).padStart(2, '0')).join(':')
+    }
+
+    expect(formatTime(86399)).toBe('23:59:59')
+    expect(formatTime(100000)).toBe('27:46:40')
+  })
+
+  it('timer increments elapsedSeconds over time', () => {
+    let elapsed = 0
+    const interval = setInterval(() => {
+      elapsed++
+    }, 1000)
+
+    vi.advanceTimersByTime(3000)
+    expect(elapsed).toBe(3)
+
+    vi.advanceTimersByTime(2000)
+    expect(elapsed).toBe(5)
+
+    clearInterval(interval)
+  })
+
+  it('timer can be paused and resumed', () => {
+    let elapsed = 0
+    let intervalId: ReturnType<typeof setInterval> | null = null
+
+    const start = () => {
+      if (!intervalId) {
+        intervalId = setInterval(() => { elapsed++ }, 1000)
+      }
+    }
+    const pause = () => {
+      if (intervalId) {
+        clearInterval(intervalId)
+        intervalId = null
+      }
+    }
+
+    start()
+    vi.advanceTimersByTime(2000)
+    expect(elapsed).toBe(2)
+
+    pause()
+    vi.advanceTimersByTime(3000)
+    expect(elapsed).toBe(2) // Should not change while paused
+
+    start()
+    vi.advanceTimersByTime(2000)
+    expect(elapsed).toBe(4)
+
+    pause()
+  })
+})