move helpers to util

1 files changed, 248 insertions, 0 deletions

diff --git a/packages/taler-wallet-core/src/coinSelection.test.ts b/packages/taler-wallet-core/src/coinSelection.test.ts
new file mode 100644
index 000000000..839cd22fb
--- /dev/null
+++ b/packages/taler-wallet-core/src/coinSelection.test.ts
@@ -0,0 +1,248 @@
+/*
+ This file is part of GNU Taler
+ (C) 2022 Taler Systems S.A.
+
+ GNU Taler is free software; you can redistribute it and/or modify it under the
+ terms of the GNU General Public License as published by the Free Software
+ Foundation; either version 3, or (at your option) any later version.
+
+ GNU Taler is distributed in the hope that it will be useful, but WITHOUT ANY
+ WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+ A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License along with
+ GNU Taler; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
+ */
+import {
+  AbsoluteTime,
+  AmountString,
+  Amounts,
+  DenomKeyType,
+  Duration,
+  j2s,
+} from "@gnu-taler/taler-util";
+import test from "ava";
+import {
+  AvailableDenom,
+  testing_greedySelectPeer,
+  testing_selectGreedy,
+} from "./coinSelection.js";
+
+const inTheDistantFuture = AbsoluteTime.toProtocolTimestamp(
+  AbsoluteTime.addDuration(AbsoluteTime.now(), Duration.fromSpec({ hours: 1 })),
+);
+
+const inThePast = AbsoluteTime.toProtocolTimestamp(
+  AbsoluteTime.subtractDuraction(
+    AbsoluteTime.now(),
+    Duration.fromSpec({ hours: 1 }),
+  ),
+);
+
+test("p2p: should select the coin", (t) => {
+  const instructedAmount = Amounts.parseOrThrow("LOCAL:2");
+  const tally = {
+    amountAcc: Amounts.zeroOfCurrency(instructedAmount.currency),
+    depositFeesAcc: Amounts.zeroOfCurrency(instructedAmount.currency),
+    lastDepositFee: Amounts.zeroOfCurrency(instructedAmount.currency),
+  };
+  const coins = testing_greedySelectPeer(
+    createCandidates([
+      {
+        amount: "LOCAL:10" as AmountString,
+        numAvailable: 5,
+        depositFee: "LOCAL:0.1" as AmountString,
+        fromExchange: "http://exchange.localhost/",
+      },
+    ]),
+    instructedAmount,
+    tally,
+  );
+
+  t.log(j2s(coins));
+
+  t.assert(coins != null);
+
+  t.deepEqual(coins, {
+    "hash0;32;http://exchange.localhost/": {
+      exchangeBaseUrl: "http://exchange.localhost/",
+      denomPubHash: "hash0",
+      maxAge: 32,
+      contributions: [Amounts.parseOrThrow("LOCAL:2.1")],
+      expireDeposit: inTheDistantFuture,
+      expireWithdraw: inTheDistantFuture,
+    },
+  });
+
+  t.deepEqual(tally, {
+    amountAcc: Amounts.parseOrThrow("LOCAL:2"),
+    depositFeesAcc: Amounts.parseOrThrow("LOCAL:0.1"),
+    lastDepositFee: Amounts.parseOrThrow("LOCAL:0.1"),
+  });
+});
+
+test("p2p: should select 3 coins", (t) => {
+  const instructedAmount = Amounts.parseOrThrow("LOCAL:20");
+  const tally = {
+    amountAcc: Amounts.zeroOfCurrency(instructedAmount.currency),
+    depositFeesAcc: Amounts.zeroOfCurrency(instructedAmount.currency),
+    lastDepositFee: Amounts.zeroOfCurrency(instructedAmount.currency),
+  };
+  const coins = testing_greedySelectPeer(
+    createCandidates([
+      {
+        amount: "LOCAL:10" as AmountString,
+        numAvailable: 5,
+        depositFee: "LOCAL:0.1" as AmountString,
+        fromExchange: "http://exchange.localhost/",
+      },
+    ]),
+    instructedAmount,
+    tally,
+  );
+
+  t.deepEqual(coins, {
+    "hash0;32;http://exchange.localhost/": {
+      exchangeBaseUrl: "http://exchange.localhost/",
+      denomPubHash: "hash0",
+      maxAge: 32,
+      contributions: [
+        Amounts.parseOrThrow("LOCAL:9.9"),
+        Amounts.parseOrThrow("LOCAL:9.9"),
+        Amounts.parseOrThrow("LOCAL:0.5"),
+      ],
+      expireDeposit: inTheDistantFuture,
+      expireWithdraw: inTheDistantFuture,
+    },
+  });
+
+  t.deepEqual(tally, {
+    amountAcc: Amounts.parseOrThrow("LOCAL:20"),
+    depositFeesAcc: Amounts.parseOrThrow("LOCAL:0.3"),
+    lastDepositFee: Amounts.parseOrThrow("LOCAL:0.1"),
+  });
+});
+
+test("p2p: can't select since the instructed amount is too high", (t) => {
+  const instructedAmount = Amounts.parseOrThrow("LOCAL:60");
+  const tally = {
+    amountAcc: Amounts.zeroOfCurrency(instructedAmount.currency),
+    depositFeesAcc: Amounts.zeroOfCurrency(instructedAmount.currency),
+    lastDepositFee: Amounts.zeroOfCurrency(instructedAmount.currency),
+  };
+  const coins = testing_greedySelectPeer(
+    createCandidates([
+      {
+        amount: "LOCAL:10" as AmountString,
+        numAvailable: 5,
+        depositFee: "LOCAL:0.1" as AmountString,
+        fromExchange: "http://exchange.localhost/",
+      },
+    ]),
+    instructedAmount,
+    tally,
+  );
+
+  t.is(coins, undefined);
+
+  t.deepEqual(tally, {
+    amountAcc: Amounts.parseOrThrow("LOCAL:49"),
+    depositFeesAcc: Amounts.parseOrThrow("LOCAL:0.5"),
+    lastDepositFee: Amounts.parseOrThrow("LOCAL:0.1"),
+  });
+});
+
+test("pay: select one coin to pay with fee", (t) => {
+  const payment = Amounts.parseOrThrow("LOCAL:2");
+  const exchangeWireFee = Amounts.parseOrThrow("LOCAL:0.1");
+  const zero = Amounts.zeroOfCurrency(payment.currency);
+  const tally = {
+    amountPayRemaining: payment,
+    amountWireFeeLimitRemaining: zero,
+    amountDepositFeeLimitRemaining: zero,
+    customerDepositFees: zero,
+    customerWireFees: zero,
+    wireFeeCoveredForExchange: new Set<string>(),
+    lastDepositFee: zero,
+  };
+  const coins = testing_selectGreedy(
+    {
+      auditors: [],
+      exchanges: [
+        {
+          exchangeBaseUrl: "http://exchange.localhost/",
+          exchangePub: "E5M8CGRDHXF1RCVP3B8TQCTDYNQ7T4XHWR5SVEQRGVVMVME41VJ0",
+        },
+      ],
+      contractTermsAmount: payment,
+      depositFeeLimit: zero,
+      wireFeeAmortization: 1,
+      wireFeeLimit: zero,
+      prevPayCoins: [],
+      wireMethod: "x-taler-bank",
+    },
+    createCandidates([
+      {
+        amount: "LOCAL:10" as AmountString,
+        numAvailable: 5,
+        depositFee: "LOCAL:0.1" as AmountString,
+        fromExchange: "http://exchange.localhost/",
+      },
+    ]),
+    { "http://exchange.localhost/": exchangeWireFee },
+    tally,
+  );
+
+  t.deepEqual(coins, {
+    "hash0;32;http://exchange.localhost/": {
+      exchangeBaseUrl: "http://exchange.localhost/",
+      denomPubHash: "hash0",
+      maxAge: 32,
+      contributions: [Amounts.parseOrThrow("LOCAL:2.2")],
+      expireDeposit: inTheDistantFuture,
+      expireWithdraw: inTheDistantFuture,
+    },
+  });
+
+  t.deepEqual(tally, {
+    amountPayRemaining: Amounts.parseOrThrow("LOCAL:2"),
+    amountWireFeeLimitRemaining: zero,
+    amountDepositFeeLimitRemaining: zero,
+    customerDepositFees: zero,
+    customerWireFees: zero,
+    wireFeeCoveredForExchange: new Set(),
+    lastDepositFee: zero,
+  });
+});
+
+function createCandidates(
+  ar: {
+    amount: AmountString;
+    depositFee: AmountString;
+    numAvailable: number;
+    fromExchange: string;
+  }[],
+): AvailableDenom[] {
+  return ar.map((r, idx) => {
+    return {
+      denomPub: {
+        age_mask: 0,
+        cipher: DenomKeyType.Rsa,
+        rsa_public_key: "PPP",
+      },
+      denomPubHash: `hash${idx}`,
+      value: r.amount,
+      feeDeposit: r.depositFee,
+      feeRefresh: "LOCAL:0" as AmountString,
+      feeRefund: "LOCAL:0" as AmountString,
+      feeWithdraw: "LOCAL:0" as AmountString,
+      stampExpireDeposit: inTheDistantFuture,
+      stampExpireLegal: inTheDistantFuture,
+      stampExpireWithdraw: inTheDistantFuture,
+      stampStart: inThePast,
+      exchangeBaseUrl: r.fromExchange,
+      numAvailable: r.numAvailable,
+      maxAge: 32,
+    };
+  });
+}