卫戍协议：盟约 web remake — initial import

Online co-op browser remake of Arknights' Stronghold Protocol: Alliance
(client-simulated combat, official waves/bonds/items/strategies, 3D board,
facing wheel, operator loadout, official emotes, deployment scripts).

test/match/merge.test.js

@@ -0,0 +1,353 @@
+// Merges (精锐), reward offers, item equip/replace/merge, consume-on-equip items (research 01 §7 + A1, 04 §2).
+import { test } from 'node:test';
+import assert from 'node:assert/strict';
+import { ERR, PHASE } from '../../shared/constants.js';
+import { DATA, makeMatch, give, giveItem, checkInvariants, chessOfTier, legalTileFor } from './harness.js';
+
+function prep(seed = 21, o = {}) {
+  const h = makeMatch({ mode: 'solo', difficulty: 'NORMAL', seed, ...o }).start();
+  h.toPrep(1);
+  h.setStage('act2autochess_m04');
+  const ps = h.ps('p_0');
+  for (const p of [...ps.board.values(), ...ps.hand.filter(Boolean)]) if (p.kind === 'chess') ps.returnCopies(p);
+  ps.board.clear();
+  ps.hand.fill(null);
+  ps.recompute();
+  ps.funds = 100;
+  return { h, m: h.m, ps };
+}
+
+/** Put chess `id` into shop slot 0 at its normal price. */
+function stock(m, ps, id, slot = 0) {
+  ps.shop.slots[slot] = { kind: 'chess', id, basePrice: m.gd.chessPrice(id), frozen: false, sold: false };
+}
+
+test('3 copies (board + hand + bought) merge into 1 elite in the hand; equipment returns; reward offer of tier level+1', () => {
+  const { m, ps } = prep();
+  const id = chessOfTier(1, (c) => c.position === 'MELEE').find((x) => m.pool.has(x));
+  const cap = m.pool.cap(id);
+  const a = give(m, ps, id, 'board', [9, 3]);
+  const b = give(m, ps, id);
+  const it1 = giveItem(m, ps, 'chess_item_1_01_e_a');
+  const it2 = giveItem(m, ps, 'chess_item_1_02_e_a');
+  assert.deepEqual(m.handle('p_0', { t: 'g.equip', itemUid: it1.uid, targetUid: a.uid }), { ok: true });
+  assert.deepEqual(m.handle('p_0', { t: 'g.equip', itemUid: it2.uid, targetUid: b.uid }), { ok: true });
+  stock(m, ps, id);
+  assert.deepEqual(m.handle('p_0', { t: 'g.buy', slot: 0 }), { ok: true });
+  const golden = DATA.chess[id].goldenId;
+  assert.ok(!ps.board.has('9,3'), 'the board copy was consumed');
+  const elite = ps.hand.find((p) => p && p.id === golden);
+  assert.ok(elite, 'elite in the hand');
+  assert.equal(elite.poolCopies, 3);
+  assert.equal(m.pool.left(id), cap - 3);
+  assert.equal(ps.countCopies(id), 0);
+  assert.ok(ps.hand.some((p) => p && p.uid === it1.uid) && ps.hand.some((p) => p && p.uid === it2.uid), 'equipment returned to the hand');
+  assert.equal(elite.items.length, 0);
+  assert.equal(ps.stats.merges, 1);
+  const offer = ps.privateView().shop.rewardOffer;
+  assert.ok(offer);
+  assert.equal(offer.tier, Math.min(ps.shop.level + 1, 6));
+  assert.equal(offer.slots.length, 3);
+  for (const s of offer.slots) { assert.equal(s.price, 0); assert.equal(DATA.chess[s.id].tier <= offer.tier, true); }
+  // take one reward (free), the offer is consumed
+  const funds = ps.funds;
+  const pick = offer.slots[1].id;
+  assert.deepEqual(m.handle('p_0', { t: 'g.reward', idx: 1 }), { ok: true });
+  assert.equal(ps.funds, funds);
+  assert.ok(ps.hand.some((p) => p && p.id === pick) || ps.hand.some((p) => p && p.id === DATA.chess[pick].goldenId));
+  assert.equal(ps.privateView().shop.rewardOffer, null);
+  assert.deepEqual(m.handle('p_0', { t: 'g.reward', idx: 0 }).error, ERR.BAD_TARGET);
+  checkInvariants(m);
+  m.dispose();
+});
+
+test('elites never merge; 风丸 merges with 2 copies; a full hand still buys the merge-completing copy', () => {
+  const { m, ps } = prep(22);
+  const id = chessOfTier(2).find((x) => m.pool.has(x) && x !== 'chess_char_2_11_a');
+  const golden = DATA.chess[id].goldenId;
+  give(m, ps, golden);
+  give(m, ps, golden);
+  stock(m, ps, golden);
+  m.handle('p_0', { t: 'g.buy', slot: 0 });
+  assert.equal(ps.hand.filter((p) => p && p.id === golden).length, 3, 'three elites stay three elites');
+  // 风丸 (chess_char_2_11_a) upgradeNum 2
+  if (m.pool.has('chess_char_2_11_a')) {
+    give(m, ps, 'chess_char_2_11_a');
+    stock(m, ps, 'chess_char_2_11_a');
+    m.handle('p_0', { t: 'g.buy', slot: 0 });
+    assert.ok(ps.hand.some((p) => p && p.id === DATA.chess.chess_char_2_11_a.goldenId), '风丸 elite after 2 copies');
+  }
+  // full hand + 2 copies in the hand: buying the 3rd completes the merge (net −1)
+  for (const p of ps.hand) if (p) ps.returnCopies(p);
+  ps.hand.fill(null);
+  const x = chessOfTier(1).filter((c) => m.pool.has(c));
+  const target = x[0];
+  give(m, ps, target);
+  give(m, ps, target);
+  for (let i = 1; ps.hand.some((p) => p == null); i++) give(m, ps, x[i]);
+  assert.ok(ps.hand.every(Boolean));
+  stock(m, ps, x[20] || x[x.length - 1], 1);
+  assert.deepEqual(m.handle('p_0', { t: 'g.buy', slot: 1 }), { error: ERR.HAND_FULL });
+  stock(m, ps, target, 0);
+  assert.deepEqual(m.handle('p_0', { t: 'g.buy', slot: 0 }), { ok: true });
+  assert.ok(ps.hand.some((p) => p && p.id === DATA.chess[target].goldenId));
+  assert.equal(ps.hand.filter(Boolean).length, 9);
+  assert.ok(ps.tempEmpty);
+  checkInvariants(m);
+  m.dispose();
+});
+
+test('merge from two board copies with a full hand overflows the elite into temp (blocks ready until resolved)', () => {
+  const { m, ps } = prep(23);
+  const ids = chessOfTier(1, (c) => c.position === 'MELEE').filter((c) => m.pool.has(c));
+  const id = ids[0];
+  give(m, ps, id, 'board', [9, 3]);
+  give(m, ps, id, 'board', [9, 4]);
+  const others = chessOfTier(2).filter((c) => m.pool.has(c));
+  for (let i = 0; ps.hand.some((p) => p == null); i++) give(m, ps, others[i]);
+  stock(m, ps, id);
+  assert.deepEqual(m.handle('p_0', { t: 'g.buy', slot: 0 }), { ok: true });
+  assert.ok(ps.temp.some((p) => p && p.id === DATA.chess[id].goldenId), 'elite overflowed into temp');
+  assert.equal(ps.board.size, 0);
+  assert.deepEqual(m.handle('p_0', { t: 'g.ready', ready: true }), { error: ERR.TEMP_NOT_EMPTY });
+  checkInvariants(m);
+  m.dispose();
+});
+
+test('reward pick respects the pool and a full hand; offers expire at prep end', () => {
+  const { h, m, ps } = prep(24);
+  ps.pushRewardOffer('merge');
+  const offer = ps.offers[0];
+  const id0 = offer.slots[0].id;
+  const taken = m.pool.take(id0, 100);
+  assert.deepEqual(m.handle('p_0', { t: 'g.reward', idx: 0 }), { error: ERR.SOLD_OUT });
+  m.pool.give(id0, taken);
+  const others = chessOfTier(3).filter((c) => m.pool.has(c) && !offer.slots.some((s) => s.id === c));
+  for (let i = 0; ps.hand.some((p) => p == null); i++) give(m, ps, others[i]);
+  assert.deepEqual(m.handle('p_0', { t: 'g.reward', idx: 0 }), { error: ERR.HAND_FULL });
+  ps.hand[0] && ps.returnCopies(ps.hand[0]);
+  ps.hand[0] = null;
+  ps.recompute();
+  assert.deepEqual(m.handle('p_0', { t: 'g.ready', ready: true }), { ok: true });
+  h.sched.runNext();
+  h.sched.runNext();
+  assert.equal(ps.offers.length, 0, 'offer gone at prep end');
+  checkInvariants(m);
+  m.dispose();
+});
+
+test('equipment: max 2 (a third replaces the oldest), identical normal items merge into golden — also when equipped', () => {
+  const { m, ps } = prep(25);
+  const id = chessOfTier(3).find((c) => m.pool.has(c));
+  const a = give(m, ps, id);
+  const i1 = giveItem(m, ps, 'chess_item_1_01_e_a');
+  const i2 = giveItem(m, ps, 'chess_item_1_02_e_a');
+  const i3 = giveItem(m, ps, 'chess_item_3_03_e_a');
+  assert.deepEqual(m.handle('p_0', { t: 'g.equip', itemUid: i1.uid, targetUid: a.uid }), { ok: true });
+  assert.deepEqual(m.handle('p_0', { t: 'g.equip', itemUid: i2.uid, targetUid: a.uid }), { ok: true });
+  assert.deepEqual(m.handle('p_0', { t: 'g.equip', itemUid: i3.uid, targetUid: a.uid }), { ok: true });
+  assert.deepEqual(a.items.map((x) => x.id), ['chess_item_1_02_e_a', 'chess_item_3_03_e_a'], 'oldest replaced (destroyed)');
+  assert.ok(!ps.find(i1.uid), 'the replaced item is gone');
+  // equip a second 坚守盾牌 onto the same carrier → merges into the golden version in the hand
+  const i4 = giveItem(m, ps, 'chess_item_1_02_e_a');
+  assert.deepEqual(m.handle('p_0', { t: 'g.equip', itemUid: i4.uid, targetUid: a.uid }), { ok: true });
+  assert.ok(ps.hand.some((p) => p && p.id === 'chess_item_1_02_e_b'), 'golden item in the hand');
+  assert.ok(!a.items.some((x) => x.id === 'chess_item_1_02_e_a'));
+  assert.equal(ps.stats.itemMerges, 1);
+  // buying an item whose twin is in the hand merges immediately (and works with a full hand)
+  const i5 = giveItem(m, ps, 'chess_item_2_03_e_a');
+  const others = chessOfTier(1).filter((c) => m.pool.has(c));
+  for (let i = 0; ps.hand.some((p) => p == null); i++) give(m, ps, others[i]);
+  ps.shop.slots[0] = { kind: 'item', id: 'chess_item_2_03_e_a', basePrice: 2, frozen: false, sold: false };
+  assert.deepEqual(m.handle('p_0', { t: 'g.buy', slot: 0 }), { ok: true });
+  assert.ok(ps.hand.some((p) => p && p.id === 'chess_item_2_03_e_b'));
+  assert.ok(!ps.find(i5.uid));
+  // golden items never merge again; non-mergeable items (upgradeNum 100) never merge
+  const g2 = giveItem(m, ps, 'chess_item_2_03_e_b', 'temp');
+  ps.checkItemMerges();
+  assert.equal([...ps.hand, ...ps.temp].filter((p) => p && p.id === 'chess_item_2_03_e_b').length, 2);
+  void g2;
+  // bad targets
+  const it = ps.hand.find((p) => p && p.kind === 'item');
+  assert.deepEqual(m.handle('p_0', { t: 'g.equip', itemUid: it.uid, targetUid: it.uid }).error, ERR.BAD_TARGET);
+  assert.deepEqual(m.handle('p_0', { t: 'g.equip', itemUid: a.uid, targetUid: a.uid }).error, ERR.BAD_TARGET);
+  checkInvariants(m);
+  m.dispose();
+});
+
+test('变形同构体 grants the bond of the other equipped item (bond counting)', () => {
+  const { m, ps } = prep(26);
+  const id = chessOfTier(1, (c) => !c.bonds.includes('victoriaShip') && c.position === 'MELEE').find((c) => m.pool.has(c));
+  const a = give(m, ps, id, 'board', [9, 3]);
+  const iso = giveItem(m, ps, 'chess_item_6_09_e_a');
+  const hammer = giveItem(m, ps, 'chess_item_1_01_e_a');
+  const before = ps.bonds.victoriaShip ? ps.bonds.victoriaShip.count : 0;
+  m.handle('p_0', { t: 'g.equip', itemUid: iso.uid, targetUid: a.uid });
+  m.handle('p_0', { t: 'g.equip', itemUid: hammer.uid, targetUid: a.uid });
+  assert.equal(ps.bonds.victoriaShip.count, before + 1, 'wearer counts as a 维多利亚 member');
+  m.dispose();
+});
+
+test('consume-on-equip built-ins: 盟约之币 funds, 随身身份牌 layers, 人事部文档 cap 9, 博士投影 promote; Arts limit', () => {
+  const { m, ps } = prep(27);
+  const id = chessOfTier(2).find((c) => m.pool.has(c));
+  const a = give(m, ps, id);
+  ps.funds = 0;
+  const coin = giveItem(m, ps, 'chess_item_1_03_e_a');
+  assert.deepEqual(m.handle('p_0', { t: 'g.equip', itemUid: coin.uid, targetUid: a.uid }), { ok: true });
+  assert.equal(ps.funds, 1);
+  assert.equal(a.items.length, 0, 'consumed, no slot used');
+  assert.ok(!ps.find(coin.uid));
+  const tag = giveItem(m, ps, 'chess_item_1_04_e_b');
+  m.handle('p_0', { t: 'g.equip', itemUid: tag.uid, targetUid: a.uid });
+  for (const b of DATA.chess[id].bonds) assert.equal(ps.layers[b], 6, `${b} +6 layers (无需激活)`);
+  const hr = giveItem(m, ps, 'chess_item_6_08_e_a');
+  m.handle('p_0', { t: 'g.equip', itemUid: hr.uid, targetUid: a.uid });
+  assert.equal(ps.deployCap, 9);
+  const holo = giveItem(m, ps, 'chess_item_5_06_e_b');
+  m.handle('p_0', { t: 'g.equip', itemUid: holo.uid, targetUid: a.uid });
+  assert.equal(a.id, DATA.chess[id].goldenId, 'golden 博士投影 promotes immediately');
+  assert.equal(a.poolCopies, 3);
+  const holo2 = giveItem(m, ps, 'chess_item_5_06_e_b');
+  assert.equal(m.handle('p_0', { t: 'g.equip', itemUid: holo2.uid, targetUid: a.uid }).error, ERR.BAD_TARGET, 'already elite');
+  // normal 博士投影: stays equipped, promotes at the next round start
+  const b = give(m, ps, chessOfTier(3).find((c) => m.pool.has(c)));
+  const holo3 = giveItem(m, ps, 'chess_item_5_06_e_a');
+  m.handle('p_0', { t: 'g.equip', itemUid: holo3.uid, targetUid: b.uid });
+  assert.equal(b.items.length, 1);
+  ps.hand.forEach((p, i) => { if (p && p.kind === 'item') ps.hand[i] = null; });
+  checkInvariants(m);
+  m.handle('p_0', { t: 'g.ready', ready: true });
+  const h = { sched: m.sched };
+  h.sched.runUntil(() => m.phase === PHASE.PREP && m.round === 2, { maxSteps: 1e6 });
+  // the bot-free solo round needs a combat → it ran; now at R2
+  assert.equal(b.id, DATA.chess[b.id].goldenId ? b.id : b.id);
+  assert.ok(m.gd.isGolden(b.id), 'promoted at the round start');
+  assert.equal(b.items.length, 0);
+  // Arts: at most 2 per round; unimplemented handlers are rejected cleanly
+  const art = giveItem(m, ps, 'chess_item_6_02_m');
+  const board = [...ps.board.entries()].find(([, p]) => p.kind === 'chess');
+  let target = board;
+  if (!target) { const c = give(m, ps, chessOfTier(1, (x) => x.position === 'MELEE').find((x) => m.pool.has(x)), 'board', [9, 3]); target = ['9,3', c]; }
+  const [r, c] = target[0].split(',').map(Number);
+  const res = m.handle('p_0', { t: 'g.art', itemUid: art.uid, row: r, col: c });
+  assert.deepEqual(res, { ok: true }, '画卷 copies the operator');
+  assert.ok(!ps.find(art.uid));
+  const art2 = giveItem(m, ps, 'chess_item_6_02_m');
+  assert.equal(m.handle('p_0', { t: 'g.art', itemUid: art2.uid, row: 12, col: 10 }).error, ERR.BAD_TARGET, 'no operator in range');
+  assert.equal(m.handle('p_0', { t: 'g.art', itemUid: art2.uid, row: 1, col: 1 }).error, ERR.BAD_TILE);
+  assert.equal(m.handle('p_0', { t: 'g.art', itemUid: a.uid, row: r, col: c }).error, ERR.BAD_TARGET);
+  checkInvariants(m);
+  m.dispose();
+});
+
+test('item merge with a full hand AND a full temp: the golden item takes the equipped twin\'s slot instead of being lost', () => {
+  const { m, ps } = prep(29);
+  const id = chessOfTier(3).find((c) => m.pool.has(c));
+  const carrier = give(m, ps, id, 'board', [10, 3]);
+  const twin = giveItem(m, ps, 'chess_item_1_02_e_a');
+  const keep = giveItem(m, ps, 'chess_item_1_01_e_a');
+  ps._detach(ps.find(twin.uid));
+  ps._detach(ps.find(keep.uid));
+  carrier.items.push(keep, twin);
+  const fill = chessOfTier(1).filter((c) => m.pool.has(c));
+  for (let i = 0; ps.hand.some((p) => p == null); i++) give(m, ps, fill[i]);
+  const fill2 = chessOfTier(2).filter((c) => m.pool.has(c));
+  for (let i = 0; ps.temp.some((p) => p == null); i++) give(m, ps, fill2[i], 'temp');
+  ps.recompute();
+  const got = ps.acquireItem('chess_item_1_02_e_a', { source: 'grant' });
+  assert.ok(got && got.id === 'chess_item_1_02_e_b', 'the merge produced the golden item');
+  assert.deepEqual(carrier.items.map((x) => x.id), ['chess_item_1_01_e_a', 'chess_item_1_02_e_b'], 'golden item equipped in the twin\'s slot');
+  assert.ok(!ps.find(twin.uid), 'the twin was consumed');
+  assert.equal(ps.stats.itemMerges, 1);
+  checkInvariants(m);
+  m.dispose();
+});
+
+test('a merge completed during SETTLE (突变细胞) keeps its reward offer for the next prep; a full hand sends the elite to a freed board tile', () => {
+  const X = 'chess_char_2_04_a';
+  const fillers = Object.values(DATA.items).filter((i) => i.itemType === 'EQUIP' && !i.isGolden && !String(i.kind || '').startsWith('consume')).map((i) => i.itemId ?? i.id).filter(Boolean);
+  for (const onBoard of [false, true]) {
+    const h = makeMatch({ mode: 'coop', difficulty: 'NORMAL', humans: 1, bots: 1, seed: 3, fake: true }).start();
+    const m = h.m;
+    h.toPrep(1);
+    const ps = h.ps('p_0');
+    for (const p of [...ps.board.values(), ...ps.hand.filter(Boolean)]) if (p.kind === 'chess') ps.returnCopies(p);
+    ps.board.clear();
+    ps.hand.fill(null);
+    ps.recompute();
+    // the mutation's tier+1 roll can only give X
+    const saved = new Map();
+    for (const [base, e] of m.pool.entries) if (e.tier === 2 && base !== X) { saved.set(base, e.left); e.left = 0; }
+    const T = chessOfTier(1, (c) => !m.gd.placeableTokens(c.chessId).length).find((id) => m.pool.has(id));
+    const holder = give(m, ps, T, 'board', legalTileFor(m, ps, T));
+    holder.items.push(ps.newPiece('item', 'chess_item_5_08_e_a'));
+    const copies = onBoard ? [0, 1].map(() => give(m, ps, X, 'board', legalTileFor(m, ps, X))) : [give(m, ps, X), give(m, ps, X)];
+    const tiles = onBoard ? copies.map((p) => ps.find(p.uid).key) : [];
+    for (let i = 0; ps.hand.some((x) => x == null); i++) giveItem(m, ps, fillers[i]);
+    let atSettle = null;
+    const settle = m.settle.bind(m);
+    m.settle = (...a) => { const r = settle(...a); atSettle = { offers: ps.offers.map((o) => o.source), merges: ps.stats.merges }; return r; };
+    h.toPrep(2);
+    for (const [base, left] of saved) m.pool.entries.get(base).left = left;
+    assert.deepEqual(atSettle, { offers: ['merge'], merges: 1 }, `${onBoard ? 'board' : 'hand'} copies: the transform completed a merge in SETTLE`);
+    const elite = ps.allChess().find((p) => p.id === m.gd.goldenIdOf(X));
+    assert.ok(elite, 'the elite survived the round start');
+    assert.deepEqual(ps.offers.map((o) => o.source), ['merge'], 'the promotion reward waits for this prep');
+    assert.ok(ps.privateView().shop.rewardOffer, 'and is shown');
+    if (onBoard) assert.ok(tiles.includes(ps.find(elite.uid).key), 'full hand outside PREP: the elite took a freed board tile, not temp');
+    assert.ok(ps.tempEmpty);
+    checkInvariants(m);
+    // it expires at the end of that prep like any other offer
+    h.drive(() => m.phase === PHASE.COMBAT && m.round === 2);
+    assert.equal(ps.offers.length, 0);
+    m.dispose();
+  }
+});
+
+test('withdrawing a summoner with a full hand: its own summon stack frees the slot (onto the stack or anywhere)', () => {
+  for (const onto of ['stack', 'other']) {
+    const { m, ps } = prep(24);
+    const hemo = give(m, ps, 'chess_char_2_02_a');
+    const [r, c] = legalTileFor(m, ps, 'chess_char_2_02_a');
+    assert.deepEqual(m.handle('p_0', { t: 'g.move', uid: hemo.uid, to: { area: 'board', row: r, col: c } }), { ok: true });
+    const stackIdx = ps.hand.findIndex((p) => p && p.kind === 'token' && p.ownerUid === hemo.uid);
+    assert.ok(stackIdx >= 0, 'its summon stack went to the hand');
+    const ids = ['chess_item_1_01_e_a', 'chess_item_1_02_e_a', 'chess_item_1_03_e_a', 'chess_item_1_04_e_a', 'chess_item_1_05_e_a', 'chess_item_2_01_e_a', 'chess_item_2_02_e_a', 'chess_item_2_03_e_a', 'chess_item_2_04_e_a'];
+    for (let i = 0; ps.hand.some((x) => x == null); i++) giveItem(m, ps, ids[i]);
+    const idx = onto === 'stack' ? stackIdx : ps.hand.findIndex((p) => p && p.kind === 'item');
+    assert.deepEqual(m.handle('p_0', { t: 'g.move', uid: hemo.uid, to: { area: 'hand', idx } }), { ok: true }, onto);
+    assert.equal(ps.find(hemo.uid).area, 'hand');
+    assert.equal(ps.hand[stackIdx], hemo, 'it takes the slot its stack left');
+    assert.ok(![...ps.hand, ...ps.temp, ...ps.board.values()].some((p) => p && p.kind === 'token'), 'its summons are gone');
+    assert.equal(ps.hand.filter((p) => p && p.kind === 'item').length, 9, 'no item was displaced');
+    checkInvariants(m);
+    m.dispose();
+  }
+});
+
+test('equipment: the replace dialog picks WHICH equipped item a third one destroys (g.equip replaceUid); equipped items are otherwise locked (g.destroy refused)', () => {
+  const { m, ps } = prep(26);
+  const a = give(m, ps, chessOfTier(3).find((c) => m.pool.has(c)));
+  const i1 = giveItem(m, ps, 'chess_item_1_01_e_a');
+  const i2 = giveItem(m, ps, 'chess_item_1_02_e_a');
+  const i3 = giveItem(m, ps, 'chess_item_3_03_e_a');
+  assert.deepEqual(m.handle('p_0', { t: 'g.equip', itemUid: i1.uid, targetUid: a.uid }), { ok: true });
+  assert.deepEqual(m.handle('p_0', { t: 'g.equip', itemUid: i2.uid, targetUid: a.uid }), { ok: true });
+  // equipped items cannot be destroyed directly
+  assert.deepEqual(m.handle('p_0', { t: 'g.destroy', uid: i1.uid }), { error: ERR.BAD_TARGET, detail: 'equipped items are locked' });
+  assert.deepEqual(a.items.map((x) => x.uid), [i1.uid, i2.uid]);
+  // a replaceUid that is not on the target changes nothing
+  assert.equal(m.handle('p_0', { t: 'g.equip', itemUid: i3.uid, targetUid: a.uid, replaceUid: i3.uid }).error, ERR.BAD_TARGET);
+  assert.ok(ps.hand.includes(i3), 'the new item stays in the hand');
+  assert.deepEqual(a.items.map((x) => x.uid), [i1.uid, i2.uid]);
+  // the player keeps the older item and replaces the newer one
+  assert.deepEqual(m.handle('p_0', { t: 'g.equip', itemUid: i3.uid, targetUid: a.uid, replaceUid: i2.uid }), { ok: true });
+  assert.deepEqual(a.items.map((x) => x.uid), [i1.uid, i3.uid]);
+  assert.ok(!ps.find(i2.uid), 'the picked item was destroyed');
+  // hand items can still be destroyed
+  const i4 = giveItem(m, ps, 'chess_item_2_03_e_a');
+  assert.deepEqual(m.handle('p_0', { t: 'g.destroy', uid: i4.uid }), { ok: true });
+  checkInvariants(m);
+  m.dispose();
+});