wallet-core: have balance item even on zero balance

Also add a test for this.

5 files changed, 76 insertions, 3 deletions

diff --git a/packages/taler-harness/src/harness/denomStructures.ts b/packages/taler-harness/src/harness/denomStructures.ts
index b12857c7e..2d5e719b0 100644
--- a/packages/taler-harness/src/harness/denomStructures.ts
+++ b/packages/taler-harness/src/harness/denomStructures.ts
@@ -136,7 +136,7 @@ export function makeNoFeeCoinConfig(curr: string): CoinConfig[] {
     const ct = 2 ** i;
 
     const unit = Math.floor(ct / 100);
-    const cent = ct % 100;
+    const cent = `${ct % 100}`.padStart(2, "0");
 
     cc.push({
       cipher: "RSA",
diff --git a/packages/taler-harness/src/integrationtests/test-wallet-balance-zero.ts b/packages/taler-harness/src/integrationtests/test-wallet-balance-zero.ts
new file mode 100644
index 000000000..7d65b60cf
--- /dev/null
+++ b/packages/taler-harness/src/integrationtests/test-wallet-balance-zero.ts
@@ -0,0 +1,64 @@
+/*
+ This file is part of GNU Taler
+ (C) 2020 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 { j2s } from "@gnu-taler/taler-util";
+import { WalletApiOperation } from "@gnu-taler/taler-wallet-core";
+import { makeNoFeeCoinConfig } from "../harness/denomStructures.js";
+import { GlobalTestState } from "../harness/harness.js";
+import {
+  createSimpleTestkudosEnvironmentV2,
+  makeTestPaymentV2,
+  withdrawViaBankV2,
+} from "../harness/helpers.js";
+
+/**
+ * Related bugs:
+ * https://bugs.taler.net/n/8323
+ */
+export async function runWalletBalanceZeroTest(t: GlobalTestState) {
+  // Set up test environment
+
+  const coinConfig = makeNoFeeCoinConfig("TESTKUDOS");
+  console.log(`coin config ${j2s(coinConfig)}`);
+  const { merchant, walletClient, exchange, bank } =
+    await createSimpleTestkudosEnvironmentV2(t, coinConfig);
+
+  const wres = await withdrawViaBankV2(t, {
+    amount: "TESTKUDOS:10",
+    bank,
+    exchange,
+    walletClient,
+  });
+  await wres.withdrawalFinishedCond;
+
+  await makeTestPaymentV2(t, {
+    walletClient,
+    merchant,
+    order: {
+      summary: "Hello, World!",
+      amount: "TESTKUDOS:10",
+    },
+  });
+
+  const bal = await walletClient.call(WalletApiOperation.GetBalances, {});
+  console.log(`${j2s(bal)}`);
+  t.assertAmountEquals(bal.balances[0].available, "TESTKUDOS:0");
+}
+
+runWalletBalanceZeroTest.suites = ["wallet"];
diff --git a/packages/taler-harness/src/integrationtests/test-wallet-balance.ts b/packages/taler-harness/src/integrationtests/test-wallet-balance.ts
index c4ca94dc0..0e4452892 100644
--- a/packages/taler-harness/src/integrationtests/test-wallet-balance.ts
+++ b/packages/taler-harness/src/integrationtests/test-wallet-balance.ts
@@ -32,7 +32,9 @@ import {
 } from "../harness/helpers.js";
 
 /**
- * Test for wallet balance error messages / different types of insufficient balance.
+ * Test wallet:
+ * - balance error messages
+ * - different types of insufficient balance.
  *
  * Related bugs:
  * https://bugs.taler.net/n/7299
diff --git a/packages/taler-harness/src/integrationtests/testrunner.ts b/packages/taler-harness/src/integrationtests/testrunner.ts
index 07bf8e34d..803e68e6b 100644
--- a/packages/taler-harness/src/integrationtests/testrunner.ts
+++ b/packages/taler-harness/src/integrationtests/testrunner.ts
@@ -87,6 +87,7 @@ import { runTermOfServiceFormatTest } from "./test-tos-format.js";
 import { runWalletBackupBasicTest } from "./test-wallet-backup-basic.js";
 import { runWalletBackupDoublespendTest } from "./test-wallet-backup-doublespend.js";
 import { runWalletBalanceNotificationsTest } from "./test-wallet-balance-notifications.js";
+import { runWalletBalanceZeroTest } from "./test-wallet-balance-zero.js";
 import { runWalletBalanceTest } from "./test-wallet-balance.js";
 import { runWalletCliTerminationTest } from "./test-wallet-cli-termination.js";
 import { runWalletConfigTest } from "./test-wallet-config.js";
@@ -202,6 +203,7 @@ const allTests: TestMainFunction[] = [
   runWalletConfigTest,
   runWalletObservabilityTest,
   runWalletDevExperimentsTest,
+  runWalletBalanceZeroTest,
 ];
 
 export interface TestRunSpec {
diff --git a/packages/taler-wallet-core/src/balance.ts b/packages/taler-wallet-core/src/balance.ts
index 3b53699ac..6dc0783c0 100644
--- a/packages/taler-wallet-core/src/balance.ts
+++ b/packages/taler-wallet-core/src/balance.ts
@@ -80,7 +80,7 @@ import {
   getExchangeScopeInfo,
   getExchangeWireDetailsInTx,
 } from "./exchanges.js";
-import { InternalWalletState, WalletExecutionContext } from "./wallet.js";
+import { WalletExecutionContext } from "./wallet.js";
 
 /**
  * Logger.
@@ -178,6 +178,10 @@ class BalancesStore {
     return this.balanceStore[balanceKey];
   }
 
+  async addZero(currency: string, exchangeBaseUrl: string): Promise<void> {
+    await this.initBalance(currency, exchangeBaseUrl);
+  }
+
   async addAvailable(
     currency: string,
     exchangeBaseUrl: string,
@@ -304,6 +308,7 @@ export async function getBalancesInsideTransaction(
 
   await tx.coinAvailability.iter().forEachAsync(async (ca) => {
     const count = ca.visibleCoinCount ?? 0;
+    await balanceStore.addZero(ca.currency, ca.exchangeBaseUrl);
     for (let i = 0; i < count; i++) {
       await balanceStore.addAvailable(
         ca.currency,