brackt/app/services/simulations/__tests__/tennis-simulator.test.ts

import { describe, it, expect } from "vitest";
import {
  eloWinProb,
  buildDraw,
  simulateMajor,
  drawFromBracket,
  buildHonoredMap,
  DEFAULT_SLAM_QP,
  type RealBracketMatch,
} from "../tennis-simulator";
import { deriveBracketQualifyingStates, getRoundConfig } from "~/models/scoring-calculator";
import { BRACKET_TEMPLATES } from "~/lib/bracket-templates";

// ─── eloWinProb ───────────────────────────────────────────────────────────────

describe("eloWinProb", () => {
  it("returns 0.5 for equal Elo", () => {
    expect(eloWinProb(1800, 1800)).toBeCloseTo(0.5, 5);
    expect(eloWinProb(1500, 1500)).toBeCloseTo(0.5, 5);
  });

  it("returns > 0.5 for positive Elo advantage, < 0.5 for negative", () => {
    expect(eloWinProb(2000, 1600)).toBeGreaterThan(0.5);
    expect(eloWinProb(1600, 2000)).toBeLessThan(0.5);
  });

  it("is symmetric: eloWinProb(a, b) + eloWinProb(b, a) = 1", () => {
    expect(eloWinProb(2000, 1600) + eloWinProb(1600, 2000)).toBeCloseTo(1.0, 5);
    expect(eloWinProb(1837, 1756) + eloWinProb(1756, 1837)).toBeCloseTo(1.0, 5);
  });

  it("returns value in (0, 1)", () => {
    expect(eloWinProb(3000, 1000)).toBeLessThan(1);
    expect(eloWinProb(3000, 1000)).toBeGreaterThan(0);
    expect(eloWinProb(1000, 3000)).toBeLessThan(1);
    expect(eloWinProb(1000, 3000)).toBeGreaterThan(0);
  });

  it("larger Elo gap → higher win probability (monotonic)", () => {
    const p200 = eloWinProb(1900, 1700);
    const p400 = eloWinProb(2100, 1700);
    expect(p400).toBeGreaterThan(p200);
  });

  it("400-point gap gives ~91% win probability (standard Elo)", () => {
    expect(eloWinProb(2200, 1800)).toBeCloseTo(0.909, 2);
  });
});

// ─── buildDraw ────────────────────────────────────────────────────────────────

function makeIds(n: number): string[] {
  return Array.from({ length: n }, (_, i) => `p${String(i + 1).padStart(3, "0")}`);
}

function makeEloMap(
  ids: string[],
  elos: number[],
  rankings?: (number | null)[]
): Map<string, { worldRanking: number | null; eloHard: number | null; eloClay: number | null; eloGrass: number | null }> {
  return new Map(ids.map((id, i) => [id, {
    worldRanking: rankings ? (rankings[i] ?? null) : i + 1, // default: rank by index (1-indexed)
    eloHard: elos[i],
    eloClay: elos[i],
    eloGrass: elos[i],
  }]));
}

describe("buildDraw", () => {
  const IDS = makeIds(128);

  it("returns exactly 128 slots", () => {
    const eloMap = makeEloMap(IDS, IDS.map((_, i) => 2000 - i));
    expect(buildDraw(IDS, eloMap)).toHaveLength(128);
  });

  it("contains every participant exactly once", () => {
    const eloMap = makeEloMap(IDS, IDS.map((_, i) => 2000 - i));
    const draw = buildDraw(IDS, eloMap);
    expect(new Set(draw).size).toBe(128);
    for (const id of IDS) {
      expect(draw).toContain(id);
    }
  });

  it("places seed 1 (highest Elo) in slot 0", () => {
    const elos = IDS.map((_, i) => 2000 - i); // descending, p001 is best
    const eloMap = makeEloMap(IDS, elos);
    const draw = buildDraw(IDS, eloMap);
    expect(draw[0]).toBe("p001"); // seed 1 always goes to slot 0
  });

  it("places seed 2 (second-highest Elo) in slot 64", () => {
    const elos = IDS.map((_, i) => 2000 - i);
    const eloMap = makeEloMap(IDS, elos);
    const draw = buildDraw(IDS, eloMap);
    expect(draw[64]).toBe("p002"); // seed 2 always goes to slot 64
  });

  it("seeds 1 and 2 are in opposite halves (slots 0–63 and 64–127)", () => {
    const elos = IDS.map((_, i) => 2000 - i);
    const eloMap = makeEloMap(IDS, elos);
    // Run multiple times to confirm it's not random
    for (let i = 0; i < 10; i++) {
      const draw = buildDraw(IDS, eloMap);
      const seed1Slot = draw.indexOf("p001");
      const seed2Slot = draw.indexOf("p002");
      const seed1InTopHalf = seed1Slot < 64;
      const seed2InTopHalf = seed2Slot < 64;
      expect(seed1InTopHalf).not.toBe(seed2InTopHalf);
    }
  });

  it("seeds by worldRanking regardless of surface (ATP/WTA ranking used for all majors)", () => {
    // p001 = world #2, p002 = world #1 — p002 should always be seed 1 regardless of surface Elo
    const eloMap = new Map<string, { worldRanking: number | null; eloHard: number | null; eloClay: number | null; eloGrass: number | null }>();
    eloMap.set("p001", { worldRanking: 2, eloHard: 2500, eloClay: 2500, eloGrass: 2500 }); // world #2 (high Elo)
    eloMap.set("p002", { worldRanking: 1, eloHard: 1400, eloClay: 1400, eloGrass: 1400 }); // world #1 (low Elo)
    for (let i = 2; i < 128; i++) {
      eloMap.set(IDS[i], { worldRanking: i + 1, eloHard: 1500, eloClay: 1500, eloGrass: 1500 });
    }

    // p002 (world #1) should always be seed 1 → slot 0, regardless of Elo
    expect(buildDraw(IDS, eloMap)[0]).toBe("p002");
  });

  it("falls back to Elo 1500 for players not in the Elo map", () => {
    // Create a map with only 1 entry; remaining 127 get fallback 1500
    const partialMap = new Map<string, { worldRanking: number | null; eloHard: number | null; eloClay: number | null; eloGrass: number | null }>();
    partialMap.set("p001", { worldRanking: 1, eloHard: 2000, eloClay: null, eloGrass: null });

    // Should not throw
    expect(() => buildDraw(IDS, partialMap)).not.toThrow();
    const draw = buildDraw(IDS, partialMap);
    expect(draw).toHaveLength(128);
  });
});

// ─── simulateMajor ────────────────────────────────────────────────────────────

describe("simulateMajor", () => {
  const IDS = makeIds(128);

  it("returns one QP result per participant in the draw", () => {
    const elos = IDS.map(() => 1500);
    const eloMap = makeEloMap(IDS, elos);
    const draw = buildDraw(IDS, eloMap);
    const results = simulateMajor(draw, eloMap, "hard");
    expect(results).toHaveLength(128);
    const ids = results.map((r) => r.participantId);
    expect(new Set(ids).size).toBe(128);
  });

  it("QP values are non-negative", () => {
    const elos = IDS.map(() => 1500);
    const eloMap = makeEloMap(IDS, elos);
    const draw = buildDraw(IDS, eloMap);
    const results = simulateMajor(draw, eloMap, "hard");
    for (const r of results) {
      expect(r.qp).toBeGreaterThanOrEqual(0);
    }
  });

  it("exactly one winner with 20 QP, one finalist with 14 QP", () => {
    const elos = IDS.map(() => 1500);
    const eloMap = makeEloMap(IDS, elos);
    const draw = buildDraw(IDS, eloMap);
    const results = simulateMajor(draw, eloMap, "hard");
    const winners   = results.filter((r) => r.qp === 20);
    const finalists = results.filter((r) => r.qp === 14);
    expect(winners).toHaveLength(1);
    expect(finalists).toHaveLength(1);
  });

  it("exactly two SF losers with 9 QP", () => {
    const elos = IDS.map(() => 1500);
    const eloMap = makeEloMap(IDS, elos);
    const draw = buildDraw(IDS, eloMap);
    const results = simulateMajor(draw, eloMap, "hard");
    expect(results.filter((r) => r.qp === 9)).toHaveLength(2);
  });

  it("exactly four QF losers with 4 QP", () => {
    const elos = IDS.map(() => 1500);
    const eloMap = makeEloMap(IDS, elos);
    const draw = buildDraw(IDS, eloMap);
    const results = simulateMajor(draw, eloMap, "hard");
    expect(results.filter((r) => r.qp === 4)).toHaveLength(4);
  });

  it("exactly eight R16 losers with 1.5 QP", () => {
    const elos = IDS.map(() => 1500);
    const eloMap = makeEloMap(IDS, elos);
    const draw = buildDraw(IDS, eloMap);
    const results = simulateMajor(draw, eloMap, "hard");
    expect(results.filter((r) => r.qp === 1.5)).toHaveLength(8);
  });

  it("remaining 112 players (R1–R3 losers) earn 0 QP", () => {
    const elos = IDS.map(() => 1500);
    const eloMap = makeEloMap(IDS, elos);
    const draw = buildDraw(IDS, eloMap);
    const results = simulateMajor(draw, eloMap, "hard");
    expect(results.filter((r) => r.qp === 0)).toHaveLength(112);
  });

  it("with a dominant player (Elo gap 1000+), they win the title almost always", () => {
    // Give p001 an overwhelming Elo advantage
    const dominantEloMap = new Map<string, { worldRanking: number | null; eloHard: number | null; eloClay: number | null; eloGrass: number | null }>();
    dominantEloMap.set("p001", { worldRanking: 1, eloHard: 5000, eloClay: 5000, eloGrass: 5000 });
    for (let i = 1; i < IDS.length; i++) {
      dominantEloMap.set(IDS[i], { worldRanking: i + 1, eloHard: 1000, eloClay: 1000, eloGrass: 1000 });
    }

    let wins = 0;
    const TRIALS = 200;
    for (let i = 0; i < TRIALS; i++) {
      const draw = buildDraw(IDS, dominantEloMap);
      const results = simulateMajor(draw, dominantEloMap, "hard");
      const p001 = results.find((r) => r.participantId === "p001");
      if (p001?.qp === 20) wins++;
    }
    // With Elo 5000 vs 1000, win probability per match ≈ 99.99% → should win almost all trials
    expect(wins).toBeGreaterThan(190);
  });

  it("uses the correct surface Elo for match win probability", () => {
    // p001 dominates on clay but is average on hard; p002 is the opposite.
    // With a 2000-point Elo gap, the dominant player wins every match.
    const surfaceMap = new Map<string, { worldRanking: number | null; eloHard: number | null; eloClay: number | null; eloGrass: number | null }>();
    surfaceMap.set("p001", { worldRanking: 1, eloHard: 1500, eloClay: 3500, eloGrass: 1500 });
    surfaceMap.set("p002", { worldRanking: 2, eloHard: 3500, eloClay: 1500, eloGrass: 1500 });
    for (let i = 2; i < 128; i++) {
      surfaceMap.set(IDS[i], { worldRanking: i + 1, eloHard: 1000, eloClay: 1000, eloGrass: 1000 });
    }

    let p001ClayWins = 0;
    let p002HardWins = 0;
    const TRIALS = 50;
    for (let i = 0; i < TRIALS; i++) {
      const draw = buildDraw(IDS, surfaceMap);
      const clayResults = simulateMajor(draw, surfaceMap, "clay");
      const hardResults = simulateMajor(draw, surfaceMap, "hard");
      if (clayResults.find((r) => r.participantId === "p001")?.qp === 20) p001ClayWins++;
      if (hardResults.find((r) => r.participantId === "p002")?.qp === 20) p002HardWins++;
    }
    // With Elo 3500 vs ≤1500, each player should win essentially every trial on their surface
    expect(p001ClayWins).toBeGreaterThan(45); // p001 dominates clay
    expect(p002HardWins).toBeGreaterThan(45); // p002 dominates hard
  });

  it("total QP distributed per major: 20+14+2*9+4*4+8*1.5 = 80 QP", () => {
    const elos = IDS.map(() => 1500);
    const eloMap = makeEloMap(IDS, elos);
    const draw = buildDraw(IDS, eloMap);
    const results = simulateMajor(draw, eloMap, "hard");
    const total = results.reduce((sum, r) => sum + r.qp, 0);
    // 20 + 14 + 9*2 + 4*4 + 1.5*8 = 20 + 14 + 18 + 16 + 12 = 80
    expect(total).toBeCloseTo(80, 5);
  });
});

// ─── TennisSimulator column-sum property ──────────────────────────────────────
// Full integration test via the simulate() method would require DB mocking.
// The column-sum guarantee is verified by the math:
// - In each simulation, exactly one player holds each rank 1–8.
// - Therefore count[rank] sums to NUM_SIMULATIONS across all players.
// - Dividing by NUM_SIMULATIONS gives column sums of exactly 1.0.
// This is verified indirectly by the simulateMajor + buildDraw tests above.

// ─── Not-participating exclusion ──────────────────────────────────────────────

describe("not-participating exclusion (tennis)", () => {
  it("falls back to full participant list when too few remain after exclusions (< 128)", () => {
    // With exactly 128 season participants and 1 excluded, activeIds.length = 127 < 128.
    // The simulator uses the full list rather than building a broken bracket.
    const IDS = makeIds(128);
    const elos = IDS.map(() => 1500);
    const eloMap = makeEloMap(IDS, elos);
    const activeIds = IDS.filter((id) => id !== "p001"); // 127 — triggers fallback
    expect(activeIds).toHaveLength(127);
    // Fallback: build with full IDS, no crash, draw is valid 128-slot bracket
    const drawIds = activeIds.length >= 128 ? activeIds : IDS;
    const draw = buildDraw(drawIds, eloMap);
    expect(draw).toHaveLength(128);
    expect(draw).toContain("p001"); // included via fallback
  });

  it("when activeIds.length >= 128, excluded player's draw slot is freed", () => {
    // 130 participants; exclude 2 → 128 remain → draw contains only active players
    const LARGE_IDS = makeIds(130);
    const elos = LARGE_IDS.map(() => 1500);
    const eloMap = makeEloMap(LARGE_IDS, elos);

    const excluded = new Set(["p001", "p002"]);
    const activeIds = LARGE_IDS.filter((id) => !excluded.has(id)); // 128 players

    expect(activeIds).toHaveLength(128);
    const draw = buildDraw(activeIds, eloMap);
    expect(draw).toHaveLength(128);
    expect(draw).not.toContain("p001");
    expect(draw).not.toContain("p002");
  });

  it("excluding the dominant player redistributes wins to the remaining field", () => {
    const LARGE_IDS = makeIds(130);
    const dominantEloMap = new Map<string, { worldRanking: number | null; eloHard: number | null; eloClay: number | null; eloGrass: number | null }>();
    dominantEloMap.set("p001", { worldRanking: 1, eloHard: 5000, eloClay: 5000, eloGrass: 5000 });
    for (let i = 1; i < LARGE_IDS.length; i++) {
      dominantEloMap.set(LARGE_IDS[i], { worldRanking: i + 1, eloHard: 1500, eloClay: 1500, eloGrass: 1500 });
    }

    const activeIds = LARGE_IDS.filter((id) => id !== "p001"); // exclude dominant player
    expect(activeIds.length).toBeGreaterThanOrEqual(128);

    const TRIALS = 100;
    let p001Wins = 0;
    for (let i = 0; i < TRIALS; i++) {
      const draw = buildDraw(activeIds, dominantEloMap);
      const results = simulateMajor(draw, dominantEloMap, "grass");
      if (results.find((r) => r.participantId === "p001")?.qp === 20) p001Wins++;
    }
    // Excluded player should not appear in any draw → 0 wins
    expect(p001Wins).toBe(0);
  });
});

describe("QP accumulation ranking (unit)", () => {
  it("seed 1 wins more often than a random player across many trials", () => {
    const IDS = makeIds(128);
    const elos = IDS.map((_, i) => 2000 - i * 3); // descending by seeding
    const eloMap = makeEloMap(IDS, elos);

    let seed1Wins = 0;
    const TRIALS = 2000;
    for (let i = 0; i < TRIALS; i++) {
      const draw = buildDraw(IDS, eloMap);
      const results = simulateMajor(draw, eloMap, "hard");
      const seed1 = results.find((r) => r.participantId === "p001");
      if (seed1?.qp === 20) seed1Wins++;
    }

    // Seed 1 has ~3 Elo points advantage per seed; should win substantially
    // more than 1/128 ≈ 0.78% of the time. Threshold at 0.02 is still well
    // above random; 2000 trials keeps std dev small enough to be non-flaky.
    const winRate = seed1Wins / TRIALS;
    expect(winRate).toBeGreaterThan(0.02); // > 2% (well above random 0.78%)
  });
});

// ─── drawFromBracket ────────────────────────────────────────────────────────────

describe("drawFromBracket", () => {
  const ids = makeIds(128);
  // 64 Round-of-128 matches: match N holds ids[2N-2], ids[2N-1].
  const fullR128 = Array.from({ length: 64 }, (_, i) => ({
    round: "Round of 128",
    matchNumber: i + 1,
    participant1Id: ids[i * 2],
    participant2Id: ids[i * 2 + 1],
  }));

  it("reconstructs a 128-slot draw in match order", () => {
    const draw = drawFromBracket(fullR128, (id) => id);
    expect(draw).not.toBeNull();
    expect(draw).toHaveLength(128);
    expect(draw?.[0]).toBe("p001");
    expect(draw?.[1]).toBe("p002");
    expect(draw?.[127]).toBe("p128");
  });

  it("returns null when the draw is not fully populated", () => {
    const partial = fullR128.slice(0, 60); // only 60 of 64 matches
    expect(drawFromBracket(partial, (id) => id)).toBeNull();
    const withNull = fullR128.map((m, i) =>
      i === 0 ? { ...m, participant1Id: null } : m
    );
    expect(drawFromBracket(withNull, (id) => id)).toBeNull();
  });

  it("applies the id translator", () => {
    const draw = drawFromBracket(fullR128, (id) => (id ? `x-${id}` : id));
    expect(draw?.[0]).toBe("x-p001");
  });
});

// ─── simulateMajor honoring a real bracket ──────────────────────────────────────

describe("simulateMajor with realBracket", () => {
  const ids = makeIds(128);
  const eloMap = makeEloMap(ids, ids.map(() => 1500));

  // A fully-decided bracket where the lower draw index always wins. Champion is
  // therefore ids[0]; the result is deterministic regardless of RNG.
  function decideBracket(draw: string[]): RealBracketMatch[] {
    const rounds = [
      "Round of 128", "Round of 64", "Round of 32", "Round of 16",
      "Quarterfinals", "Semifinals", "Final",
    ];
    const order = new Map(draw.map((id, i) => [id, i]));
    const matches: RealBracketMatch[] = [];
    let current = [...draw];
    for (const round of rounds) {
      const next: string[] = [];
      for (let i = 0; i < current.length; i += 2) {
        const p1 = current[i];
        const p2 = current[i + 1];
        const winner = (order.get(p1) ?? 0) < (order.get(p2) ?? 0) ? p1 : p2;
        matches.push({ round, matchNumber: i / 2 + 1, winnerId: winner, isComplete: true });
        next.push(winner);
      }
      current = next;
    }
    return matches;
  }

  it("honors a fully-decided bracket deterministically (champion = draw[0])", () => {
    const draw = [...ids];
    const realBracket = decideBracket(draw);
    const results = simulateMajor(draw, eloMap, "hard", { realBracket });
    const champ = results.find((r) => r.qp === DEFAULT_SLAM_QP.winner);
    expect(champ?.participantId).toBe(draw[0]);
    // Structural counts are unchanged by honoring.
    expect(results.filter((r) => r.qp === DEFAULT_SLAM_QP.winner)).toHaveLength(1);
    expect(results.filter((r) => r.qp === DEFAULT_SLAM_QP.finalist)).toHaveLength(1);
    expect(results.filter((r) => r.qp === DEFAULT_SLAM_QP.sf)).toHaveLength(2);
    expect(results.filter((r) => r.qp === DEFAULT_SLAM_QP.qf)).toHaveLength(4);
    expect(results.filter((r) => r.qp === DEFAULT_SLAM_QP.r16)).toHaveLength(8);
  });

  it("honors a completed Final winner even against a heavy Elo underdog", () => {
    // Underdog at draw[0] (low Elo) but the Final is recorded as their win.
    const draw = [...ids];
    const skewed = makeEloMap(draw, draw.map((_, i) => (i === 0 ? 100 : 3000)));
    const realBracket = decideBracket(draw); // draw[0] wins everything
    const results = simulateMajor(draw, skewed, "hard", { realBracket });
    const champ = results.find((r) => r.qp === DEFAULT_SLAM_QP.winner);
    expect(champ?.participantId).toBe(draw[0]);
  });

  it("uses config QP values from opts.qp", () => {
    const draw = [...ids];
    const realBracket = decideBracket(draw);
    const qp = { winner: 100, finalist: 70, sf: 40, qf: 20, r16: 5 };
    const results = simulateMajor(draw, eloMap, "hard", { realBracket, qp });
    expect(results.find((r) => r.participantId === draw[0])?.qp).toBe(100);
    expect(results.filter((r) => r.qp === 70)).toHaveLength(1);
    expect(results.filter((r) => r.qp === 5)).toHaveLength(8);
  });
});

// ─── tennis_128 bracket scoring (QP placement derivation) ───────────────────────

describe("tennis_128 qualifying bracket scoring", () => {
  it("derives placements 1/2/3/5/9 from the tennis_128 round config", () => {
    const template = BRACKET_TEMPLATES.tennis_128;
    // A wins R16 → QF → SF → Final (champion). Losers exit at each scoring round.
    const matches = [
      { round: "Round of 16", winnerId: "A", loserId: "I", participant1Id: "A", participant2Id: "I" },
      { round: "Quarterfinals", winnerId: "A", loserId: "E", participant1Id: "A", participant2Id: "E" },
      { round: "Semifinals", winnerId: "A", loserId: "C", participant1Id: "A", participant2Id: "C" },
      { round: "Final", winnerId: "A", loserId: "B", participant1Id: "A", participant2Id: "B" },
    ];
    const states = deriveBracketQualifyingStates(
      matches,
      template.rounds,
      (round) => getRoundConfig(round, "tennis_128")
    );
    expect(states.get("A")?.placement).toBe(1); // champion
    expect(states.get("B")?.placement).toBe(2); // Final loser
    expect(states.get("C")).toMatchObject({ placement: 3, tieCount: 2 }); // SF loser
    expect(states.get("E")).toMatchObject({ placement: 5, tieCount: 4 }); // QF loser
    expect(states.get("I")).toMatchObject({ placement: 9, tieCount: 8 }); // R16 loser
  });
});

// ─── exclusions (not-participating) + prebuilt honored map ──────────────────────

describe("simulateMajor exclusions & prebuilt honored", () => {
  const ids = makeIds(128);

  it("a withdrawn player walks over (earns 0 QP) even with a dominant Elo", () => {
    // draw[0] would otherwise win almost everything; excluding them must zero them.
    const dominant = makeEloMap(ids, ids.map((_, i) => (i === 0 ? 5000 : 1000)));
    const excluded = new Set([ids[0]]);
    for (let t = 0; t < 20; t++) {
      const results = simulateMajor(ids, dominant, "hard", { excluded });
      expect(results.find((r) => r.participantId === ids[0])?.qp).toBe(0);
    }
  });

  it("a completed match is still honored even if the winner is later excluded", () => {
    // Fully-decided bracket says draw[0] wins; excluding them must NOT override a
    // recorded real result (the match already happened).
    function decide(draw: string[]): RealBracketMatch[] {
      const rounds = [
        "Round of 128", "Round of 64", "Round of 32", "Round of 16",
        "Quarterfinals", "Semifinals", "Final",
      ];
      const order = new Map(draw.map((id, i) => [id, i]));
      const matches: RealBracketMatch[] = [];
      let cur = [...draw];
      for (const round of rounds) {
        const next: string[] = [];
        for (let i = 0; i < cur.length; i += 2) {
          const w = (order.get(cur[i]) ?? 0) < (order.get(cur[i + 1]) ?? 0) ? cur[i] : cur[i + 1];
          matches.push({ round, matchNumber: i / 2 + 1, winnerId: w, isComplete: true });
          next.push(w);
        }
        cur = next;
      }
      return matches;
    }
    const honored = buildHonoredMap(decide(ids));
    const eloMap = makeEloMap(ids, ids.map(() => 1500));
    const results = simulateMajor(ids, eloMap, "hard", {
      honored,
      excluded: new Set([ids[0]]),
    });
    expect(results.find((r) => r.qp === DEFAULT_SLAM_QP.winner)?.participantId).toBe(ids[0]);
  });

  it("prebuilt honored map produces the same champion as realBracket input", () => {
    const realBracket: RealBracketMatch[] = [
      { round: "Final", matchNumber: 1, winnerId: null, isComplete: false },
    ];
    const honored = buildHonoredMap(realBracket);
    // Empty honored (no completed matches) → no crash, full simulation runs.
    const eloMap = makeEloMap(ids, ids.map(() => 1500));
    const results = simulateMajor(ids, eloMap, "hard", { honored });
    expect(results.filter((r) => r.qp === DEFAULT_SLAM_QP.winner)).toHaveLength(1);
  });
});