taler-typescript-core

commit 86ad465fe282ba77bf50359a7f91ebbccc5be41b
parent ab42503d8c53af369e2abb1170c68d7f7013dfa2
Author: Florian Dold <dold@taler.net>
Date:   Thu,  3 Sep 2026 15:51:25 +0200

wallet-core: test change distribution and master keys in selection

Diffstat:
M
packages/taler-wallet-core/src/coinSelection.test.ts
 | 
83
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++---------------

1 file changed, 68 insertions(+), 15 deletions(-)
diff --git a/packages/taler-wallet-core/src/coinSelection.test.ts b/packages/taler-wallet-core/src/coinSelection.test.ts
@@ -958,7 +958,7 @@ test("demo: deposit max after withdraw raw 13", (t) => {
   // current wallet impl fee 0.14
 });
 
-test("overpay when remaining < depositFee", (t) => {
+test("change never drops a contribution below its deposit fee", (t) => {
   const instructedAmount = Amounts.parseOrThrow("LOCAL:2.1");
   const tally = emptyTallyForPeerPayment({
     instructedAmount,
@@ -990,22 +990,75 @@ test("overpay when remaining < depositFee", (t) => {
 
   assert.ok(coins != null);
 
-  assert.deepStrictEqual(coins, {
-    "hash0;32;http://exchange.localhost/": {
-      exchangeBaseUrl: "http://exchange.localhost/",
-      exchangeMasterPub: "123",
-      denomPubHash: "hash0",
-      maxAge: 32,
-      contributions: [Amounts.parseOrThrow("LOCAL:2")],
+  // The excess of 0.9 over the instructed amount comes out of the smallest
+  // coin only down to its deposit fee; the rest comes out of the next one.
+  // The exchange refuses a coin whose contribution is below its fee.
+  let total = Amounts.zeroOfCurrency("LOCAL");
+  for (const sel of Object.values(coins)) {
+    for (const contribution of sel.contributions) {
+      assert.ok(
+        Amounts.cmp(contribution, "LOCAL:0.2") >= 0,
+        `contribution ${Amounts.stringify(contribution)} below deposit fee`,
+      );
+      total = Amounts.add(total, contribution).amount;
+    }
+  }
+  assert.strictEqual(Amounts.stringify(total), "LOCAL:2.1");
+  assert.deepStrictEqual(
+    coins["hash1;32;http://exchange.localhost/"]?.contributions,
+    [Amounts.parseOrThrow("LOCAL:0.2")],
+  );
+  assert.deepStrictEqual(
+    coins["hash0;32;http://exchange.localhost/"]?.contributions,
+    [Amounts.parseOrThrow("LOCAL:1.9")],
+  );
+});
+
+test("coins of one denomination under two master keys stay separate", (t) => {
+  const instructedAmount = Amounts.parseOrThrow("LOCAL:2");
+  const tally = emptyTallyForPeerPayment({
+    instructedAmount,
+  });
+  tally.amountDepositFeeLimitRemaining = Amounts.parseOrThrow("LOCAL:1");
+
+  // The same denomination, re-signed under the exchange's new master key.
+  const candidates = createCandidates([
+    {
+      amount: "LOCAL:1" as AmountString,
+      numAvailable: 1,
+      depositFee: "LOCAL:0" as AmountString,
+      fromExchange: "http://exchange.localhost/",
+      fromMasterPub: "OLDKEY",
     },
-    "hash1;32;http://exchange.localhost/": {
-      exchangeBaseUrl: "http://exchange.localhost/",
-      exchangeMasterPub: "123",
-      denomPubHash: "hash1",
-      maxAge: 32,
-      contributions: [Amounts.parseOrThrow("LOCAL:0.1")],
+    {
+      amount: "LOCAL:1" as AmountString,
+      numAvailable: 1,
+      depositFee: "LOCAL:0" as AmountString,
+      fromExchange: "http://exchange.localhost/",
+      fromMasterPub: "NEWKEY",
     },
-  });
+  ]);
+  candidates[1].denomPubHash = candidates[0].denomPubHash;
+  const coins = testing_selectGreedy(
+    {
+      wireFeesPerExchange: {},
+    },
+    candidates,
+    tally,
+  );
+
+  assert.ok(coins != null);
+  // Each entry is later looked up in the database by its master key, so
+  // the two coins must not be folded into one entry.
+  const entries = Object.values(coins);
+  assert.strictEqual(entries.length, 2);
+  assert.deepStrictEqual(
+    entries.map((e) => e.exchangeMasterPub).sort(),
+    ["NEWKEY", "OLDKEY"],
+  );
+  for (const e of entries) {
+    assert.deepStrictEqual(e.contributions, [Amounts.parseOrThrow("LOCAL:1")]);
+  }
 });
 
 test("DD91 removes redundant small coins after ascending selection", (t) => {