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diff --git a/packages/taler-wallet-core/src/util/coinSelection-test.ts b/packages/taler-wallet-core/src/util/coinSelection-test.ts
new file mode 100644
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+++ b/packages/taler-wallet-core/src/util/coinSelection-test.ts
@@ -0,0 +1,186 @@
+/*
+ This file is part of GNU Taler
+ (C) 2021 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/>
+ */
+
+/**
+ * Imports.
+ */
+import test from "ava";
+import { AmountJson, Amounts } from "..";
+import { AvailableCoinInfo, selectPayCoins } from "./coinSelection";
+
+function a(x: string): AmountJson {
+  const amt = Amounts.parse(x);
+  if (!amt) {
+    throw Error("invalid amount");
+  }
+  return amt;
+}
+
+function fakeAci(current: string, feeDeposit: string): AvailableCoinInfo {
+  return {
+    availableAmount: a(current),
+    coinPub: "foobar",
+    denomPub: "foobar",
+    feeDeposit: a(feeDeposit),
+    exchangeBaseUrl: "https://example.com/",
+  };
+}
+
+test("coin selection 1", (t) => {
+  const acis: AvailableCoinInfo[] = [
+    fakeAci("EUR:1.0", "EUR:0.1"),
+    fakeAci("EUR:1.0", "EUR:0.0"),
+  ];
+
+  const res = selectPayCoins({
+    candidates: {
+      candidateCoins: acis,
+      wireFeesPerExchange: {},
+    },
+    contractTermsAmount: a("EUR:2.0"),
+    depositFeeLimit: a("EUR:0.1"),
+    wireFeeLimit: a("EUR:0"),
+    wireFeeAmortization: 1,
+  });
+
+  if (!res) {
+    t.fail();
+    return;
+  }
+  t.true(res.coinPubs.length === 2);
+  t.pass();
+});
+
+test("coin selection 2", (t) => {
+  const acis: AvailableCoinInfo[] = [
+    fakeAci("EUR:1.0", "EUR:0.5"),
+    fakeAci("EUR:1.0", "EUR:0.0"),
+    // Merchant covers the fee, this one shouldn't be used
+    fakeAci("EUR:1.0", "EUR:0.0"),
+  ];
+
+  const res = selectPayCoins({
+    candidates: {
+      candidateCoins: acis,
+      wireFeesPerExchange: {},
+    },
+    contractTermsAmount: a("EUR:2.0"),
+    depositFeeLimit: a("EUR:0.5"),
+    wireFeeLimit: a("EUR:0"),
+    wireFeeAmortization: 1,
+  });
+
+  if (!res) {
+    t.fail();
+    return;
+  }
+  t.true(res.coinPubs.length === 2);
+  t.pass();
+});
+
+test("coin selection 3", (t) => {
+  const acis: AvailableCoinInfo[] = [
+    fakeAci("EUR:1.0", "EUR:0.5"),
+    fakeAci("EUR:1.0", "EUR:0.5"),
+    // this coin should be selected instead of previous one with fee
+    fakeAci("EUR:1.0", "EUR:0.0"),
+  ];
+
+  const res = selectPayCoins({
+    candidates: {
+      candidateCoins: acis,
+      wireFeesPerExchange: {},
+    },
+    contractTermsAmount: a("EUR:2.0"),
+    depositFeeLimit: a("EUR:0.5"),
+    wireFeeLimit: a("EUR:0"),
+    wireFeeAmortization: 1,
+  });
+
+  if (!res) {
+    t.fail();
+    return;
+  }
+  t.true(res.coinPubs.length === 2);
+  t.pass();
+});
+
+test("coin selection 4", (t) => {
+  const acis: AvailableCoinInfo[] = [
+    fakeAci("EUR:1.0", "EUR:0.5"),
+    fakeAci("EUR:1.0", "EUR:0.5"),
+    fakeAci("EUR:1.0", "EUR:0.5"),
+  ];
+
+  const res = selectPayCoins({
+    candidates: {
+      candidateCoins: acis,
+      wireFeesPerExchange: {},
+    },
+    contractTermsAmount: a("EUR:2.0"),
+    depositFeeLimit: a("EUR:0.5"),
+    wireFeeLimit: a("EUR:0"),
+    wireFeeAmortization: 1,
+  });
+
+  if (!res) {
+    t.fail();
+    return;
+  }
+  t.true(res.coinPubs.length === 3);
+  t.pass();
+});
+
+test("coin selection 5", (t) => {
+  const acis: AvailableCoinInfo[] = [
+    fakeAci("EUR:1.0", "EUR:0.5"),
+    fakeAci("EUR:1.0", "EUR:0.5"),
+    fakeAci("EUR:1.0", "EUR:0.5"),
+  ];
+
+  const res = selectPayCoins({
+    candidates: {
+      candidateCoins: acis,
+      wireFeesPerExchange: {},
+    },
+    contractTermsAmount: a("EUR:4.0"),
+    depositFeeLimit: a("EUR:0.2"),
+    wireFeeLimit: a("EUR:0"),
+    wireFeeAmortization: 1,
+  });
+
+  t.true(!res);
+  t.pass();
+});
+
+test("coin selection 6", (t) => {
+  const acis: AvailableCoinInfo[] = [
+    fakeAci("EUR:1.0", "EUR:0.5"),
+    fakeAci("EUR:1.0", "EUR:0.5"),
+  ];
+  const res = selectPayCoins({
+    candidates: {
+      candidateCoins: acis,
+      wireFeesPerExchange: {},
+    },
+    contractTermsAmount: a("EUR:2.0"),
+    depositFeeLimit: a("EUR:0.2"),
+    wireFeeLimit: a("EUR:0"),
+    wireFeeAmortization: 1,
+  });
+  t.true(!res);
+  t.pass();
+});