Test: Add unit tests for date formatting utilities

Author: rashmithachamikara

portal/frontend/src/__tests__/DateTimeUtils.test.ts

@@ -0,0 +1,54 @@
+import { describe, expect, it } from 'vitest'
+import { formatEpochSeconds, formatIsoDateTime } from '../utils/dateTime'
+
+const DATE_TIME_FORMAT_OPTIONS: Intl.DateTimeFormatOptions = {
+  year: 'numeric',
+  month: '2-digit',
+  day: '2-digit',
+  hour: '2-digit',
+  minute: '2-digit',
+  second: '2-digit',
+  hour12: false,
+  timeZone: 'UTC',
+}
+
+describe('formatEpochSeconds', () => {
+  it('returns placeholder for undefined, null, and non-finite values', () => {
+    expect(formatEpochSeconds(undefined)).toBe('-')
+    expect(formatEpochSeconds(null)).toBe('-')
+    expect(formatEpochSeconds(Number.NaN)).toBe('-')
+    expect(formatEpochSeconds(Number.POSITIVE_INFINITY)).toBe('-')
+  })
+
+  it('formats epoch zero as a valid date instead of placeholder', () => {
+    const expected = new Date(0).toLocaleString('en-US', DATE_TIME_FORMAT_OPTIONS)
+
+    expect(formatEpochSeconds(0, DATE_TIME_FORMAT_OPTIONS, 'en-US')).toBe(expected)
+  })
+
+  it('formats a valid epoch value using locale and options', () => {
+    const epochInSeconds = 1710000000
+    const expected = new Date(epochInSeconds * 1000).toLocaleString(
+      'en-US',
+      DATE_TIME_FORMAT_OPTIONS,
+    )
+
+    expect(formatEpochSeconds(epochInSeconds, DATE_TIME_FORMAT_OPTIONS, 'en-US')).toBe(expected)
+  })
+})
+
+describe('formatIsoDateTime', () => {
+  it('returns placeholder for empty or invalid values', () => {
+    expect(formatIsoDateTime(undefined)).toBe('-')
+    expect(formatIsoDateTime(null)).toBe('-')
+    expect(formatIsoDateTime('')).toBe('-')
+    expect(formatIsoDateTime('not-a-date')).toBe('-')
+  })
+
+  it('formats valid ISO date-time using locale and options', () => {
+    const isoDateTime = '2026-03-02T15:29:57Z'
+    const expected = new Date(isoDateTime).toLocaleString('en-US', DATE_TIME_FORMAT_OPTIONS)
+
+    expect(formatIsoDateTime(isoDateTime, DATE_TIME_FORMAT_OPTIONS, 'en-US')).toBe(expected)
+  })
+})