Add unit tests for data file rotation utility functions

- Implement tests for writing data files with rotation, ensuring backups are created only on changes.
- Verify that old backups are rotated correctly and the maximum number of backups is maintained.
- Test restoration of backups while preserving the current state as a backup.
- Utilize Vitest for testing framework and manage temporary file storage during tests.

scripts/data-backup-restore.js

@@ -0,0 +1,163 @@
+#!/usr/bin/env node
+
+import path from 'path'
+import {
+  getBackupDirectoryForDataFile,
+  listDataFileBackups,
+  restoreDataFileBackup
+} from '../server/utils/data-file-rotation.js'
+
+const FILES = {
+  'users.json': getDataPath('users.json'),
+  'sessions.json': getDataPath('sessions.json'),
+  'members.json': getDataPath('members.json'),
+  'newsletter-subscribers.json': getDataPath('newsletter-subscribers.json'),
+  'news.json': getDataPath('news.json'),
+  'termine.csv': getDataPath('termine.csv'),
+  'contact-requests.json': getDataPath('contact-requests.json')
+}
+
+function getDataPath(filename) {
+  const cwd = process.cwd()
+  if (cwd.endsWith('.output')) {
+    return path.join(cwd, '../server/data', filename)
+  }
+  return path.join(cwd, 'server/data', filename)
+}
+
+function parseArg(name) {
+  const index = process.argv.findIndex((arg) => arg === name)
+  if (index === -1) return null
+  const next = process.argv[index + 1]
+  if (!next || next.startsWith('--')) return null
+  return next
+}
+
+function hasFlag(name) {
+  return process.argv.includes(name)
+}
+
+function printUsage() {
+  console.log('Verwendung:')
+  console.log('  node scripts/data-backup-restore.js list [--file users.json]')
+  console.log('  node scripts/data-backup-restore.js restore --file users.json --latest')
+  console.log('  node scripts/data-backup-restore.js restore --file users.json --backup <backup-datei.bak>')
+  console.log('')
+  console.log('Optionen:')
+  console.log('  --file    Eine der bekannten Daten-Dateien')
+  console.log('  --latest  Stellt das neueste Backup wieder her')
+  console.log('  --backup  Konkreter Backup-Dateiname (*.bak)')
+  console.log('')
+  console.log('Bekannte Dateien:')
+  Object.keys(FILES).forEach((name) => console.log(`  - ${name}`))
+}
+
+async function listCommand() {
+  const requestedFile = parseArg('--file')
+  const names = requestedFile ? [requestedFile] : Object.keys(FILES)
+
+  for (const name of names) {
+    const dataPath = FILES[name]
+    if (!dataPath) {
+      console.error(`Unbekannte Datei: ${name}`)
+      process.exitCode = 1
+      continue
+    }
+
+    const backups = await listDataFileBackups(dataPath)
+    const backupDir = getBackupDirectoryForDataFile(dataPath)
+
+    console.log(`\n${name}`)
+    console.log(`  Datenpfad: ${dataPath}`)
+    console.log(`  Backup-Ordner: ${backupDir}`)
+
+    if (backups.length === 0) {
+      console.log('  Backups: keine')
+      continue
+    }
+
+    console.log(`  Backups (${backups.length}, neuestes zuerst):`)
+    backups.slice(0, 15).forEach((backup) => {
+      console.log(`    - ${backup}`)
+    })
+    if (backups.length > 15) {
+      console.log(`    ... (${backups.length - 15} weitere)`)
+    }
+  }
+}
+
+async function restoreCommand() {
+  const fileName = parseArg('--file')
+  if (!fileName) {
+    console.error('Fehlend: --file <datei>')
+    printUsage()
+    process.exit(1)
+  }
+
+  const dataPath = FILES[fileName]
+  if (!dataPath) {
+    console.error(`Unbekannte Datei: ${fileName}`)
+    process.exit(1)
+  }
+
+  const backups = await listDataFileBackups(dataPath)
+  if (backups.length === 0) {
+    console.error(`Keine Backups gefunden für ${fileName}`)
+    process.exit(1)
+  }
+
+  const backupName = parseArg('--backup')
+  const latest = hasFlag('--latest')
+
+  let targetBackup = backupName
+  if (!targetBackup && latest) {
+    targetBackup = backups[0]
+  }
+
+  if (!targetBackup) {
+    console.error('Bitte --latest oder --backup <name> angeben')
+    process.exit(1)
+  }
+
+  if (!backups.includes(targetBackup)) {
+    console.error(`Backup nicht gefunden: ${targetBackup}`)
+    console.error('Nutzen Sie zuerst: node scripts/data-backup-restore.js list --file <datei>')
+    process.exit(1)
+  }
+
+  const result = await restoreDataFileBackup(dataPath, targetBackup)
+
+  console.log(`Wiederherstellung abgeschlossen: ${fileName}`)
+  console.log(`  Eingespieltes Backup: ${targetBackup}`)
+  if (result.backupPath) {
+    console.log(`  Backup des vorherigen Zustands: ${result.backupPath}`)
+  }
+}
+
+async function main() {
+  const command = process.argv[2]
+
+  if (!command || command === '--help' || command === '-h') {
+    printUsage()
+    return
+  }
+
+  if (command === 'list') {
+    await listCommand()
+    return
+  }
+
+  if (command === 'restore') {
+    await restoreCommand()
+    return
+  }
+
+  console.error(`Unbekannter Befehl: ${command}`)
+  printUsage()
+  process.exit(1)
+}
+
+main().catch((error) => {
+  console.error('Fehler im Backup/Restore-Skript:', error)
+  process.exit(1)
+})