From 3f06af2084e28681f40e038590b37eefb1f4c0c2 Mon Sep 17 00:00:00 2001
From: Chris Hibbert <hibbert@agoric.com>
Date: Fri, 5 Aug 2022 17:49:45 -0700
Subject: [PATCH] feat: add E(userSeat).wasWantSatisfied()

---
 packages/zoe/src/zoeService/zoeSeat.js      |  9 +++
 packages/zoe/test/unitTests/zcf/test-zcf.js | 73 +++++++++++++++++++++
 2 files changed, 82 insertions(+)

diff --git a/packages/zoe/src/zoeService/zoeSeat.js b/packages/zoe/src/zoeService/zoeSeat.js
index b38e1b244d6..abf3199c6e8 100644
--- a/packages/zoe/src/zoeService/zoeSeat.js
+++ b/packages/zoe/src/zoeService/zoeSeat.js
@@ -4,6 +4,7 @@ import { makePromiseKit } from '@endo/promise-kit';
 import { makeNotifierKit } from '@agoric/notifier';
 import { E } from '@endo/eventual-send';
 import { Far } from '@endo/marshal';
+import { AmountMath } from '@agoric/ertp';
 
 import { handlePKitWarning } from '../handleWarning.js';
 
@@ -95,6 +96,14 @@ export const makeZoeSeatAdminKit = (
 
     getCurrentAllocationJig: async () => currentAllocation,
     getAllocationNotifierJig: async () => notifier,
+
+    wasWantSatisfied: async () => {
+      return E.when(payoutPromiseKit.promise, () =>
+        Object.keys(proposal.want).every(kwd =>
+          AmountMath.isGTE(currentAllocation[kwd], proposal.want[kwd]),
+        ),
+      );
+    },
   });
 
   return { userSeat, zoeSeatAdmin, notifier };
diff --git a/packages/zoe/test/unitTests/zcf/test-zcf.js b/packages/zoe/test/unitTests/zcf/test-zcf.js
index eecedccef50..35c253a6734 100644
--- a/packages/zoe/test/unitTests/zcf/test-zcf.js
+++ b/packages/zoe/test/unitTests/zcf/test-zcf.js
@@ -1413,3 +1413,76 @@ test(`zcf.setOfferFilter - legal lists`, async t => {
   t.is(await zcf.setOfferFilter(['fooOffer', 'barOffer']), undefined);
   t.is(await zcf.setOfferFilter(['fooOffer: ', 'bar Offer']), undefined);
 });
+
+test('wasWantSatisfied: no', async t => {
+  const { zcf } = await setupZCFTest();
+  const doubloonMint = await zcf.makeZCFMint('Doubloons');
+  const yenMint = await zcf.makeZCFMint('Yen');
+  const { brand: doubloonBrand } = doubloonMint.getIssuerRecord();
+  const { brand: yenBrand } = yenMint.getIssuerRecord();
+  const yenAmount = AmountMath.make(yenBrand, 100n);
+  const proposal = harden({
+    give: { DownPayment: yenAmount },
+    want: { Bonus: AmountMath.make(doubloonBrand, 1_000_000n) },
+  });
+
+  const { zcfSeat: mintSeat, userSeat: payoutSeat } = zcf.makeEmptySeatKit();
+  yenMint.mintGains(harden({ Cost: yenAmount }), mintSeat);
+  mintSeat.exit();
+  const payout = await E(payoutSeat).getPayout('Cost');
+  const payment = { DownPayment: payout };
+
+  const { zcfSeat, userSeat } = await makeOffer(
+    zcf.getZoeService(),
+    zcf,
+    proposal,
+    payment,
+  );
+
+  await zcfSeat.exit();
+  t.false(await E(userSeat).wasWantSatisfied());
+});
+
+test('wasWantSatisfied: yes', async t => {
+  const { zcf } = await setupZCFTest();
+  const doubloonMint = await zcf.makeZCFMint('Doubloons');
+  const { brand: doubloonBrand } = doubloonMint.getIssuerRecord();
+  const doubloonAmount = AmountMath.make(doubloonBrand, 100n);
+
+  const proposal = harden({
+    want: { Bonus: doubloonAmount },
+  });
+  const { zcfSeat, userSeat } = await makeOffer(
+    zcf.getZoeService(),
+    zcf,
+    proposal,
+  );
+  doubloonMint.mintGains(harden({ Bonus: doubloonAmount }), zcfSeat);
+
+  await zcfSeat.exit();
+  t.true(await E(userSeat).wasWantSatisfied());
+});
+
+test('wasWantSatisfied as promise', async t => {
+  const { zcf } = await setupZCFTest();
+  const doubloonMint = await zcf.makeZCFMint('Doubloons');
+  const { brand: doubloonBrand } = doubloonMint.getIssuerRecord();
+  const doubloonAmount = AmountMath.make(doubloonBrand, 100n);
+
+  const proposal = harden({
+    want: { Bonus: doubloonAmount },
+  });
+  const { zcfSeat, userSeat } = await makeOffer(
+    zcf.getZoeService(),
+    zcf,
+    proposal,
+  );
+
+  const outcome = E.when(E(userSeat).wasWantSatisfied(), result =>
+    t.true(result),
+  );
+  doubloonMint.mintGains(harden({ Bonus: doubloonAmount }), zcfSeat);
+
+  await zcfSeat.exit();
+  await outcome;
+});