ENH - clock app

frontend/src/utils/clock.test.ts

@@ -1,9 +1,21 @@
 import { describe, expect, it } from 'vitest'
-import { elapsedMilliseconds, remainingMilliseconds } from './clock'
+import {
+  elapsedMilliseconds,
+  formatTimer,
+  remainingMilliseconds,
+  timerPickerMilliseconds,
+  timerPickerValue,
+} from './clock'
 describe('timestamp clocks', () => {
   it('derives elapsed and remaining time without an interval state', () => {
     expect(elapsedMilliseconds(500, 1000, 2500)).toBe(2000)
     expect(remainingMilliseconds(5000, 1000, 2500)).toBe(3500)
     expect(remainingMilliseconds(100, 1000, 2500)).toBe(0)
   })
+
+  it('formats and parses timer durations with hours, minutes, and seconds', () => {
+    expect(formatTimer(3_661_000)).toBe('01:01:01')
+    expect(timerPickerValue(3_661_000)).toBe('01:01:01')
+    expect(timerPickerMilliseconds('01:01:01')).toBe(3_661_000)
+  })
 })