Fix amount serialization

3 files changed, 15 insertions, 5 deletions

diff --git a/bank/src/main/kotlin/tech/libeufin/bank/TalerCommon.kt b/bank/src/main/kotlin/tech/libeufin/bank/TalerCommon.kt
index 39f024d4..0b866e6b 100644
--- a/bank/src/main/kotlin/tech/libeufin/bank/TalerCommon.kt
+++ b/bank/src/main/kotlin/tech/libeufin/bank/TalerCommon.kt
@@ -288,9 +288,12 @@ class TalerAmount {
     }
 
     override fun toString(): String {
-        val fracNoTrailingZero = this.frac.toString().dropLastWhile { it == '0' }
-        if (fracNoTrailingZero.isEmpty()) return "$currency:$value"
-        return "$currency:$value.$fracNoTrailingZero"
+        if (frac == 0) {
+            return "$currency:$value"
+        } else {
+            return "$currency:$value.${frac.toString().padStart(8, '0')}"
+                .dropLastWhile { it == '0' } // Trim useless fractional trailing 0
+        }
     }
 
     internal object Serializer : KSerializer<TalerAmount> {
diff --git a/bank/src/test/kotlin/AmountTest.kt b/bank/src/test/kotlin/AmountTest.kt
index 650b3fd6..ecae5768 100644
--- a/bank/src/test/kotlin/AmountTest.kt
+++ b/bank/src/test/kotlin/AmountTest.kt
@@ -92,6 +92,13 @@ class AmountTest {
     }
 
     @Test
+    fun parseRoundTrip() {
+        for (amount in listOf("EUR:4", "EUR:0.02", "EUR:4.12")) {
+            assertEquals(amount, TalerAmount(amount).toString())
+        }
+    }
+
+    @Test
     fun normalize() {
         assertEquals(TalerAmount("EUR:6"), TalerAmount(4L, 2 * TalerAmount.FRACTION_BASE, "EUR").normalize())
         assertEquals(TalerAmount("EUR:6.00000001"), TalerAmount(4L, 2 * TalerAmount.FRACTION_BASE + 1, "EUR").normalize())
diff --git a/bank/src/test/kotlin/TalerApiTest.kt b/bank/src/test/kotlin/TalerApiTest.kt
index 9aa3b562..a9cbf711 100644
--- a/bank/src/test/kotlin/TalerApiTest.kt
+++ b/bank/src/test/kotlin/TalerApiTest.kt
@@ -55,11 +55,11 @@ class TalerApiTest {
     )
     
 
-    suspend fun Database.genTransfer(from: String, to: BankAccount) {
+    suspend fun Database.genTransfer(from: String, to: BankAccount, amount: String = "KUDOS:10") {
         talerTransferCreate(
             req = TransferRequest(
                 request_uid = randHashCode(),
-                amount = TalerAmount(10, 0, "KUDOS"),
+                amount = TalerAmount(amount),
                 exchange_base_url = "http://exchange.example.com/",
                 wtid = randShortHashCode(),
                 credit_account ="${stripIbanPayto(to.internalPaytoUri)}"