joerglohrerde/snapshot/tests/cache.test.ts

import { assertEquals } from '@std/assert'
import { join } from '@std/path'
import { readCache, writeCache, type CacheState } from '../src/core/cache.ts'

Deno.test('readCache: file fehlt -> undefined', async () => {
  const dir = await Deno.makeTempDir()
  const path = join(dir, 'cache.json')
  const cache = await readCache(path)
  assertEquals(cache, undefined)
})

Deno.test('writeCache + readCache: round-trip', async () => {
  const dir = await Deno.makeTempDir()
  const path = join(dir, 'cache.json')
  const state: CacheState = { lastKnownGoodCount: 27, deletedCoords: ['30023:P:dead'] }
  await writeCache(path, state)
  const out = await readCache(path)
  assertEquals(out, state)
})

Deno.test('readCache wirft bei korruptem cache-file', async () => {
  const dir = await Deno.makeTempDir()
  const path = join(dir, 'cache.json')
  await Deno.writeTextFile(path, '{"unsinn": 42}')
  let threw = false
  try {
    await readCache(path)
  } catch (err) {
    threw = true
    if (!(err instanceof Error)) throw err
    if (!err.message.includes('Cache-File')) throw err
  }
  if (!threw) throw new Error('readCache haette werfen sollen')
})