deepseek-harness/packages/session/session-persistence-sqlite/tests/compression-unprofitable.spec.ts

import { describe, expect, it, vi } from 'vitest'
import type { SessionEvent } from '@deepseek-ai/dsh-session'

vi.mock('node:zlib', async (importOriginal) => {
  const actual = await importOriginal<typeof import('node:zlib')>()
  return {
    ...actual,
    zstdCompressSync: (input: ArrayBufferView) => Buffer.alloc(input.byteLength + 1),
  }
})

import { bindRecord, ZSTD_DATA_THRESHOLD_BYTES } from '../src/compression.ts'

describe('SQLite compression fallback', () => {
  it('keeps large data as text when its Zstandard frame is not smaller', () => {
    const event = {
      type: 'assistant/message',
      seq: 0,
      time: 1,
      data: { text: 'x'.repeat(ZSTD_DATA_THRESHOLD_BYTES) },
    } as unknown as SessionEvent

    expect(typeof bindRecord(event).data).toBe('string')
  })
})