decision/frontend/tests/engine/threshold.spec.ts

/**
 * Ported from backend/app/tests/test_threshold.py — every pytest case
 * exists here with the same expected values. Exact integer expectations
 * were cross-checked by executing the Python engine (backend/.venv).
 *
 * Real-world reference case:
 *   Vote Engagement Forgeron v2.0.0 (Feb 2026)
 *   wotSize=7224, votesFor=97, votesAgainst=23, total=120
 *   params M=50, B=0.1, G=0.2 => threshold=94 => adopted (97 >= 94)
 */
import { describe, expect, it } from 'vitest'
import { smithThreshold, techcommThreshold, wotThreshold } from '../../app/engine/threshold'

// ---------------------------------------------------------------------------
// WoT threshold: real-world vote Forgeron
// ---------------------------------------------------------------------------

describe('wotThreshold — Forgeron reference case', () => {
  it('forgeron vote passes (97 for out of 120 total, wot=7224)', () => {
    const threshold = wotThreshold(7224, 120, 50, 0.1, 0.2)
    // With low participation (120/7224 ~ 1.66%), near-unanimity is required.
    // The historical threshold was 94, and 97 >= 94.
    expect(97).toBeGreaterThanOrEqual(threshold)
    // The threshold should be high relative to total votes (inertia effect)
    expect(threshold).toBeGreaterThan(60)
  })

  it('forgeron threshold value is in a reasonable range', () => {
    const threshold = wotThreshold(7224, 120, 50, 0.1, 0.2)
    // At ~1.66% participation, inertia should push threshold close to 78-95%
    // of total votes.
    expect(threshold).toBeGreaterThanOrEqual(80)
    expect(threshold).toBeLessThanOrEqual(120)
  })

  it('forgeron threshold is exactly 94 (Python cross-check)', () => {
    expect(wotThreshold(7224, 120, 50, 0.1, 0.2)).toBe(94)
  })
})

// ---------------------------------------------------------------------------
// WoT threshold: low participation
// ---------------------------------------------------------------------------

describe('wotThreshold — low participation', () => {
  it('10 votes out of 7224 requires near-unanimity', () => {
    const threshold = wotThreshold(7224, 10, 50, 0.1, 0.2)
    // With participation ratio 10/7224 ~ 0.14%, threshold should be
    // very close to totalVotes (near-unanimity).
    expect(threshold).toBeGreaterThanOrEqual(9)
    expect(threshold).toBeLessThanOrEqual(10)
    // Python cross-check: exact value
    expect(threshold).toBe(9)
  })
})

// ---------------------------------------------------------------------------
// WoT threshold: high participation
// ---------------------------------------------------------------------------

describe('wotThreshold — high participation', () => {
  it('3000 votes out of 7224 approaches simple majority', () => {
    const threshold = wotThreshold(7224, 3000, 50, 0.1, 0.2)
    // With ~42% participation, the inertia factor diminishes.
    const simpleMajority = Math.ceil(3000 * 0.5)
    expect(threshold).toBeGreaterThanOrEqual(simpleMajority)
    // Should be noticeably less than near-unanimity
    expect(threshold).toBeLessThan(2700)
    // Python cross-check: exact value
    expect(threshold).toBe(1742)
  })
})

// ---------------------------------------------------------------------------
// WoT threshold: edge cases
// ---------------------------------------------------------------------------

describe('wotThreshold — edge cases', () => {
  it('zero total votes => ceil(C + B^W)', () => {
    const threshold = wotThreshold(7224, 0, 50, 0.1, 0.2)
    // B^W = 0.1^7224 is effectively 0
    const expected = Math.ceil(0.0 + 0.1 ** 7224)
    expect(threshold).toBe(expected)
    expect(threshold).toBe(0)
  })

  it('throws on wotSize = 0', () => {
    expect(() => wotThreshold(0, 10)).toThrow(/wotSize/)
  })

  it('throws on negative totalVotes', () => {
    expect(() => wotThreshold(100, -1)).toThrow(/totalVotes/)
  })

  it('throws on majorityPct out of range', () => {
    expect(() => wotThreshold(100, 10, 150)).toThrow(/majorityPct/)
  })
})

// ---------------------------------------------------------------------------
// WoT threshold: Python↔TS parity (values executed from backend/.venv)
// ---------------------------------------------------------------------------

describe('wotThreshold — Python parity cases', () => {
  it('T > W (100 wot, 150 votes) => 69', () => {
    expect(wotThreshold(100, 150, 50, 0.1, 0.2)).toBe(69)
  })

  it('T = W (full participation) => simple majority 50', () => {
    expect(wotThreshold(100, 100, 50, 0.1, 0.2)).toBe(50)
  })

  it('constantBase C=10 on Forgeron numbers => 96', () => {
    expect(wotThreshold(7224, 120, 50, 0.1, 0.2, 10.0)).toBe(96)
  })

  it('majorityPct 80 on Forgeron numbers => 110', () => {
    expect(wotThreshold(7224, 120, 80, 0.1, 0.2)).toBe(110)
  })

  it('minimal corpus W=1, T=1 => 1', () => {
    expect(wotThreshold(1, 1, 50, 0.1, 0.2)).toBe(1)
  })

  it('W=10, T=5 => 3', () => {
    expect(wotThreshold(10, 5, 50, 0.1, 0.2)).toBe(3)
  })
})

// ---------------------------------------------------------------------------
// Smith threshold
// ---------------------------------------------------------------------------

describe('smithThreshold — ceil(smithSize ^ S)', () => {
  it('smithSize=20, exponent=0.1 => ceil(20^0.1) = 2', () => {
    const result = smithThreshold(20, 0.1)
    expect(result).toBe(Math.ceil(20 ** 0.1))
    // 20^0.1 ~ 1.35, ceil => 2
    expect(result).toBe(2)
  })

  it('smithSize=1 => ceil(1^0.1) = 1', () => {
    expect(smithThreshold(1, 0.1)).toBe(1)
  })

  it('throws on smithSize = 0', () => {
    expect(() => smithThreshold(0)).toThrow()
  })

  it('smithSize=1000, exponent=0.5 => 32 (Python cross-check)', () => {
    expect(smithThreshold(1000, 0.5)).toBe(32)
  })
})

// ---------------------------------------------------------------------------
// TechComm threshold
// ---------------------------------------------------------------------------

describe('techcommThreshold — ceil(cotecSize ^ T)', () => {
  it('cotecSize=5, exponent=0.1 => ceil(5^0.1) = 2', () => {
    const result = techcommThreshold(5, 0.1)
    expect(result).toBe(Math.ceil(5 ** 0.1))
    // 5^0.1 ~ 1.175, ceil => 2
    expect(result).toBe(2)
  })

  it('cotecSize=1 => 1', () => {
    expect(techcommThreshold(1, 0.1)).toBe(1)
  })

  it('throws on cotecSize = 0', () => {
    expect(() => techcommThreshold(0)).toThrow()
  })
})