Add iCal download composable with RFC 5545 VEVENT generation

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

frontend/src/composables/__tests__/useIcalDownload.spec.ts

@@ -0,0 +1,120 @@
+import { describe, it, expect } from 'vitest'
+import { generateIcs } from '../useIcalDownload'
+
+describe('generateIcs', () => {
+  const baseEvent = {
+    eventToken: '550e8400-e29b-41d4-a716-446655440000',
+    title: 'Sommerfest am See',
+    dateTime: '2026-07-15T18:00:00+02:00',
+    location: 'Stadtpark Berlin',
+    description: 'Bring your own drinks',
+  }
+
+  it('generates valid VCALENDAR wrapper', () => {
+    const ics = generateIcs(baseEvent)
+    expect(ics).toMatch(/^BEGIN:VCALENDAR\r\n/)
+    expect(ics).toMatch(/\r\nEND:VCALENDAR\r\n$/)
+  })
+
+  it('includes VERSION and PRODID', () => {
+    const ics = generateIcs(baseEvent)
+    expect(ics).toContain('VERSION:2.0\r\n')
+    expect(ics).toContain('PRODID:-//fete//EN\r\n')
+  })
+
+  it('generates valid VEVENT block', () => {
+    const ics = generateIcs(baseEvent)
+    expect(ics).toContain('BEGIN:VEVENT\r\n')
+    expect(ics).toContain('END:VEVENT\r\n')
+  })
+
+  it('sets UID from eventToken', () => {
+    const ics = generateIcs(baseEvent)
+    expect(ics).toContain('UID:550e8400-e29b-41d4-a716-446655440000@fete\r\n')
+  })
+
+  it('sets DTSTART in UTC format', () => {
+    const ics = generateIcs(baseEvent)
+    expect(ics).toContain('DTSTART:20260715T160000Z\r\n')
+  })
+
+  it('does NOT include DTEND or DURATION', () => {
+    const ics = generateIcs(baseEvent)
+    expect(ics).not.toContain('DTEND')
+    expect(ics).not.toContain('DURATION')
+  })
+
+  it('sets SUMMARY from title', () => {
+    const ics = generateIcs(baseEvent)
+    expect(ics).toContain('SUMMARY:Sommerfest am See\r\n')
+  })
+
+  it('sets LOCATION when present', () => {
+    const ics = generateIcs(baseEvent)
+    expect(ics).toContain('LOCATION:Stadtpark Berlin\r\n')
+  })
+
+  it('sets DESCRIPTION when present', () => {
+    const ics = generateIcs(baseEvent)
+    expect(ics).toContain('DESCRIPTION:Bring your own drinks\r\n')
+  })
+
+  it('omits LOCATION when not provided', () => {
+    const { location: _location, ...noLocation } = baseEvent
+    const ics = generateIcs(noLocation)
+    expect(ics).not.toContain('LOCATION')
+  })
+
+  it('omits DESCRIPTION when not provided', () => {
+    const { description: _description, ...noDesc } = baseEvent
+    const ics = generateIcs(noDesc)
+    expect(ics).not.toContain('DESCRIPTION')
+  })
+
+  it('includes SEQUENCE:0', () => {
+    const ics = generateIcs(baseEvent)
+    expect(ics).toContain('SEQUENCE:0\r\n')
+  })
+
+  it('includes DTSTAMP in UTC format', () => {
+    const ics = generateIcs(baseEvent)
+    expect(ics).toMatch(/DTSTAMP:\d{8}T\d{6}Z\r\n/)
+  })
+
+  it('escapes commas in text fields', () => {
+    const ics = generateIcs({ ...baseEvent, title: 'Hello, World' })
+    expect(ics).toContain('SUMMARY:Hello\\, World\r\n')
+  })
+
+  it('escapes semicolons in text fields', () => {
+    const ics = generateIcs({ ...baseEvent, description: 'foo; bar' })
+    expect(ics).toContain('DESCRIPTION:foo\\; bar\r\n')
+  })
+
+  it('escapes backslashes in text fields', () => {
+    const ics = generateIcs({ ...baseEvent, title: 'path\\to' })
+    expect(ics).toContain('SUMMARY:path\\\\to\r\n')
+  })
+
+  it('escapes newlines in text fields', () => {
+    const ics = generateIcs({ ...baseEvent, description: 'line1\nline2' })
+    expect(ics).toContain('DESCRIPTION:line1\\nline2\r\n')
+  })
+
+  it('produces deterministic output for the same input', () => {
+    const ics1 = generateIcs(baseEvent)
+    const ics2 = generateIcs(baseEvent)
+    // DTSTAMP changes with time, so strip it for comparison
+    const strip = (s: string) => s.replace(/DTSTAMP:\d{8}T\d{6}Z\r\n/, '')
+    expect(strip(ics1)).toBe(strip(ics2))
+  })
+
+  it('uses CRLF line endings throughout', () => {
+    const ics = generateIcs(baseEvent)
+    const lines = ics.split('\r\n')
+    // Every "line" split by CRLF should not contain a bare LF
+    for (const line of lines) {
+      expect(line).not.toContain('\n')
+    }
+  })
+})