import { describe, it, expect } from 'vitest'
import { createBoundedDedup } from './bounded-dedup'

describe('createBoundedDedup', () => {
  it('reports a key only the first time it is seen', () => {
    const dedup = createBoundedDedup(10)
    expect(dedup.firstSeen('a')).toBe(true)
    expect(dedup.firstSeen('a')).toBe(false)
    expect(dedup.firstSeen('b')).toBe(true)
  })

  it('evicts wholesale at the cap, so a bounded footprint beats permanence', () => {
    const dedup = createBoundedDedup(2)
    expect(dedup.firstSeen('a')).toBe(true)
    expect(dedup.firstSeen('b')).toBe(true)
    // Cap hit — the set clears, then records 'c'.
    expect(dedup.firstSeen('c')).toBe(true)
    // 'a' was evicted: it may report once more (storm guard, not a ledger).
    expect(dedup.firstSeen('a')).toBe(true)
    // 'c' survived the post-eviction add.
    expect(dedup.firstSeen('c')).toBe(false)
  })
})