vyndr/tests/unit/probabilityContract.test.js

'use strict';

/**
 * THE CONTRACT'S ONE JOB: never answer "the calibrator is not supported here"
 * with a number we have already measured to be wrong.
 */
const pc = require('../../src/services/model/probabilityContract');
const svc = require('../../src/services/model/probabilityContractService');
const reg = require('../../src/services/model/calibrationRegistry');

const ERA = 'engine1@2026-08-07-fullwindow';
const read = (p, over = {}) => ({ sport: 'mlb', stat: 'hits', model_version: ERA, p_win: p, ...over });
// A stand-in shaped like the real map: monotone, flattening, correcting downward.
const iso = (p) => Math.round((0.42 + 0.26 * p) * 1000) / 1000;
const deps = { estimate: iso };

describe('probability object and states', () => {
  it('serves a calibrated number inside certified raw support', () => {
    const r = pc.resolve(read(0.65), deps);
    expect(r.probability_state).toBe(pc.STATE.CERTIFIED_CALIBRATED);
    expect(r.served_probability).toBe(iso(0.65));
    expect(pc.isCertified(r)).toBe(true);
  });

  it('NO RAW FALLBACK — an uncertified region serves no number at all', () => {
    for (const p of [0.85, 0.90, 0.95, 0.99]) {
      const r = pc.resolve(read(p), deps);
      expect(r.probability_state).toBe(pc.STATE.UNCERTIFIED);
      expect(r.served_probability).toBeNull();
      // the specific defect: served must not silently become the raw value
      expect(r.served_probability).not.toBe(p);
    }
  });

  it('raw probability is preserved in every state, including refusals', () => {
    for (const p of [0.45, 0.55, 0.85, 0.95]) {
      expect(pc.resolve(read(p), deps).raw_model_probability).toBe(p);
    }
    expect(pc.resolve(read(0.9), deps).raw_model_probability).toBe(0.9);
  });

  it('a different model era is a different forecaster — VERSION_MISMATCH, no number', () => {
    const r = pc.resolve(read(0.65, { model_version: 'engine1@2026-07-20' }), deps);
    expect(r.probability_state).toBe(pc.STATE.VERSION_MISMATCH);
    expect(r.served_probability).toBeNull();
  });

  it('another stat or sport is UNSUPPORTED, never quietly served', () => {
    for (const o of [{ stat: 'total_bases' }, { stat: 'rbi' }, { sport: 'wnba' }, { sport: 'nba' }]) {
      const r = pc.resolve(read(0.65, o), deps);
      expect(r.probability_state).toBe(pc.STATE.UNSUPPORTED);
      expect(r.served_probability).toBeNull();
    }
  });

  it('an absent or out-of-range raw probability is INVALID, not coerced', () => {
    for (const p of [null, undefined, NaN, -0.1, 1.4, 'x']) {
      const r = pc.resolve(read(p), deps);
      expect(r.probability_state).toBe(pc.STATE.INVALID);
      expect(r.served_probability).toBeNull();
    }
  });

  it('refuses when the estimator declines inside its own support', () => {
    const r = pc.resolve(read(0.65), { estimate: () => null });
    expect(r.probability_state).toBe(pc.STATE.UNCERTIFIED);
    expect(r.served_probability).toBeNull();
  });

  it('the certified band is half-open and expressed in the RAW input domain', () => {
    expect(pc.inCertifiedRawBand(pc.MLB_HITS.certified_bands, 0.50)).toBe(true);
    expect(pc.inCertifiedRawBand(pc.MLB_HITS.certified_bands, 0.799)).toBe(true);
    expect(pc.inCertifiedRawBand(pc.MLB_HITS.certified_bands, 0.80)).toBe(false);
    expect(pc.inCertifiedRawBand(pc.MLB_HITS.certified_bands, 0.499)).toBe(false);
  });
});

describe('the served function is non-decreasing across its support', () => {
  it('never moves backwards as raw confidence rises', () => {
    let prev = null;
    for (let x = 0.30; x <= 1.0001; x += 0.001) {
      const p = Math.round(x * 1000) / 1000;
      const r = pc.resolve(read(p), deps);
      if (r.served_probability == null) continue;
      if (prev != null) expect(r.served_probability).toBeGreaterThanOrEqual(prev);
      prev = r.served_probability;
    }
  });

  it('a gap is an absence, not a step down to raw', () => {
    const inside = pc.resolve(read(0.799), deps).served_probability;
    const outside = pc.resolve(read(0.80), deps);
    expect(inside).not.toBeNull();
    expect(outside.served_probability).toBeNull();
    expect(outside.served_probability).not.toBe(0.80);
  });
});

describe('actionability law', () => {
  const odds = -115;
  it('derives EV, Kelly and VALUE from the SERVED probability', () => {
    const r = pc.resolve(read(0.65), deps);
    const d = pc.derivedClaims(r, odds);
    expect(d.available).toBe(true);
    expect(d.computed_from).toBe('served_probability');
    const { evPct } = require('../../src/utils/devig');
    expect(d.ev_pct).toBe(evPct(r.served_probability, odds));
    expect(d.ev_pct).not.toBe(evPct(0.65, odds));      // NOT from raw
  });

  it('withdraws EV, Kelly and VALUE entirely when no probability is certified', () => {
    for (const p of [0.85, 0.95]) {
      const d = pc.derivedClaims(pc.resolve(read(p), deps), odds);
      expect(d.available).toBe(false);
      expect(d.ev_pct).toBeNull();
      expect(d.kelly).toBeNull();
      expect(d.value).toBeNull();
    }
  });

  it('never computes a derived claim from raw behind the scenes', () => {
    const { evPct } = require('../../src/utils/devig');
    const { quarterKelly } = require('../../src/utils/kelly');
    const d = pc.derivedClaims(pc.resolve(read(0.91), deps), odds);
    expect(d.ev_pct).not.toBe(evPct(0.91, odds));
    expect(d.kelly).not.toEqual(quarterKelly(0.91, odds));
    expect(d.kelly).toBeNull();
  });

  it('a VERSION_MISMATCH withdraws actionability too', () => {
    const d = pc.derivedClaims(pc.resolve(read(0.65, { model_version: 'other' }), deps), odds);
    expect(d.available).toBe(false);
  });
});

describe('confidence display', () => {
  it('shows an exact number only when the state is certified', () => {
    const c = pc.confidenceDisplay(pc.resolve(read(0.65), deps));
    expect(c.exact_probability).toBe(iso(0.65));
    expect(c.calibrated).toBe(true);
  });

  it('shows NO exact confidence when uncertified — and never the raw value', () => {
    const c = pc.confidenceDisplay(pc.resolve(read(0.91), deps));
    expect(c.exact_probability).toBeNull();
    expect(c.exact_pct).toBeNull();
    expect(c.calibrated).toBe(false);
    expect(c.label).toBe('Confidence not calibrated');
    expect(JSON.stringify(c)).not.toContain('0.91');
  });
});

describe('the artifact records its own adjudication', () => {
  it('is pinned to the current model era and the isotonic estimator', () => {
    expect(pc.MLB_HITS.model_version).toBe(ERA);
    expect(pc.MLB_HITS.estimator_type).toBe(pc.ESTIMATOR.ISOTONIC);
    expect(pc.MLB_HITS.estimator_version).toBeTruthy();
    expect(pc.MLB_HITS.certification_version).toBeTruthy();
  });

  it('certifies nothing above raw 0.80 — the region where raw is most wrong', () => {
    for (const p of [0.80, 0.85, 0.90, 0.95]) {
      expect(pc.inCertifiedRawBand(pc.MLB_HITS.certified_bands, p)).toBe(false);
    }
  });

  it('holds ONE contract — no other sport or stat is certified', () => {
    expect(Object.keys(pc.CONTRACTS)).toEqual(['mlb:hits']);
  });

  it('the held-out interval it records excludes zero', () => {
    expect(pc.MLB_HITS.evidence.ci95[1]).toBeLessThan(0);
  });
});

describe('the registry already asked the right question', () => {
  it('serves() tests certified bands against the RAW p_win, not the output', () => {
    const r = reg.createRegistry();
    r.deploy('hits', { lodo_pass: true, ci: [-0.006, -0.001], map: { x: [0], y: [0] },
      certified_bands: [[0.50, 0.80]] });
    expect(r.serves('hits', 0.65).serve).toBe(true);
    expect(r.serves('hits', 0.90).serve).toBe(false);
  });

  it('a refusal names the reason and never proposes raw', () => {
    const r = reg.createRegistry();
    r.deploy('hits', { lodo_pass: true, ci: [-0.006, -0.001], map: {}, certified_bands: [[0.50, 0.80]] });
    const out = r.serves('hits', 0.92);
    expect(out.serve).toBe(false);
    expect(JSON.stringify(out)).not.toContain('0.92');
  });
});

describe('probabilityContractService', () => {
  it('returns null — not raw — when there is no settled history', async () => {
    const built = await svc.build({}, { calibrationService: { fromLedger: async () => null } });
    expect(built).toBeNull();
  });

  it('takes the MAP and never the blocked calibrate() gate', async () => {
    const cal = require('../../src/services/model/calibration');
    const map = cal.fitIsotonic(Array.from({ length: 600 }, (_, i) => {
      const p = 0.40 + (i % 55) / 100;
      return { p, won: i % 3 === 0 ? 0 : 1, date: `d${i % 12}` };
    }), { minTotal: 200 });
    const calibrateSpy = jest.fn(() => ({ p_calibrated: 0.99, calibrated: true }));
    const built = await svc.build({}, { calibrationService: {
      fromLedger: async () => ({ map, fit_n: 600, fitted_through: 'd11', calibrate: calibrateSpy }) } });
    expect(built).not.toBeNull();
    const r = built.resolve({ model_version: ERA, p_win: 0.65 });
    expect(r.probability_state).toBe(pc.STATE.CERTIFIED_CALIBRATED);
    expect(calibrateSpy).not.toHaveBeenCalled();
  });

  it('support comes from the artifact, so a nightly refit cannot widen it', async () => {
    const built = await svc.build({}, { calibrationService: {
      fromLedger: async () => ({ map: { x: [0, 1], y: [0.5, 0.9] }, fit_n: 900, fitted_through: 'd9',
        bands: [[0.0, 1.0]] }) } });          // fit claims the whole range
    expect(built.resolve({ model_version: ERA, p_win: 0.95 }).probability_state).toBe(pc.STATE.UNCERTIFIED);
  });
});