be: cover the czech text, the holder's delegates and the fallbacks, so a regression fails the build

modules/moneta-api/src/test/java/cz/insuit/moneta/MonetaClientTest.java

@@ -264,6 +264,40 @@ void aPendingMovementHasOnlyTheDateItWasEntered() {
             assertNull(pending.bookingDate());
             assertNull(pending.valueDate());
             assertEquals(new PaymentSymbols(null, null, null), pending.symbols());
+            // Czech text arrives intact only while the body is decoded as UTF-8.
+            assertEquals("Okamžitá platba", pending.message());
+        }
+
+        @Test
+        void aBookedMovementKeepsItsCzechText() {
+            answer(TRANSACTIONS, 200, fixture("live/booked.json"));
+
+            var booked = client.transactions(TOKEN, "acc-1", FROM, TO).getFirst();
+
+            assertTrue(booked.raw().contains("OKAMŽITÁ ÚHRADA"), booked.raw());
+        }
+
+        @Test
+        void anUnknownWayOfPayingIsOtherAndKeptInRaw() {
+            var page = (ObjectNode) JSON.readTree(movement("BOOK", "CRDT"));
+            ((ObjectNode) page.get("transactions").get(0))
+                    .withObject("/entryDetails/transactionDetails/references")
+                    .put("clearingSystemReference", "PAYMENT_BY_CARRIER_PIGEON");
+            answer(TRANSACTIONS, 200, page.toString());
+
+            var movement = client.transactions(TOKEN, "acc-1", FROM, TO).getFirst();
+
+            assertEquals(Transaction.Method.OTHER, movement.method());
+            assertTrue(movement.raw().contains("PAYMENT_BY_CARRIER_PIGEON"), movement.raw());
+        }
+
+        @Test
+        void aCancellationIsReversed() {
+            var page = (ObjectNode) JSON.readTree(movement("BOOK", "DBIT"));
+            ((ObjectNode) page.get("transactions").get(0)).put("reversalIndicator", true);
+            answer(TRANSACTIONS, 200, page.toString());
+
+            assertTrue(client.transactions(TOKEN, "acc-1", FROM, TO).getFirst().reversed());
         }
 
         @Test
@@ -551,6 +585,13 @@ void anySeparatorCopiedFromAStatementOrAPageMatches() {
             assertEquals("acc-1", Objects.requireNonNull(found).id());
         }
 
+        @Test
+        @SuppressWarnings("NullAway") // a Java caller can still pass null
+        void aNullIbanIsRefusedBeforeAnyRequest() {
+            assertThrows(NullPointerException.class, () -> client.accountByIban(TOKEN, null));
+            assertTrue(requests.isEmpty());
+        }
+
         @ParameterizedTest
         @ValueSource(strings = {"", "  ", "\u00A0", "-"})
         void aBlankIbanIsTheCallersMistakeNotARevokedAccount(String blank) {
@@ -605,6 +646,33 @@ void aHolderReadsTheAccountsAgainForEveryIban() {
                             .count());
         }
 
+        @Test
+        void aHolderReadsTheAccountItNames() {
+            answer(ACCOUNTS, 200, TWO_ACCOUNTS_ONE_WITHOUT_IBAN);
+            answer(ACCOUNTS + "/acc-0/balance", 200, fixture("live/balance.json"));
+            answer(ACCOUNTS + "/acc-0/transactions", 200, NO_TRANSACTIONS);
+            var me = client.with(TOKEN);
+
+            assertEquals(
+                    List.of("acc-0", "acc-1"),
+                    me.accounts().stream().map(Account::id).toList());
+            me.balance("acc-0");
+            me.transactions("acc-0").between(FROM, TO).list();
+
+            assertEquals(
+                    List.of(ACCOUNTS, ACCOUNTS + "/acc-0/balance", ACCOUNTS + "/acc-0/transactions"),
+                    requests.stream().map(r -> r.getRequestURI().getPath()).toList());
+        }
+
+        @Test
+        void aHolderBalanceWithoutAnAccountRefusesATokenWithTwo() {
+            answer(ACCOUNTS, 200, TWO_ACCOUNTS_ONE_WITHOUT_IBAN);
+
+            var refused = assertThrows(
+                    IllegalStateException.class, () -> client.with(TOKEN).balance());
+            assertTrue(String.valueOf(refused.getMessage()).contains("opens 2 accounts"), refused.getMessage());
+        }
+
         @Test
         void aQueryWithoutAnAccountRefusesATokenWithTwo() {
             answer(ACCOUNTS, 200, """

modules/moneta-api/src/test/java/cz/insuit/moneta/MoneyTest.java

@@ -24,6 +24,19 @@ void neverRounds() {
         assertEquals(new BigDecimal("100"), new Money(new BigDecimal("100.0"), Currency.getInstance("JPY")).amount());
     }
 
+    @Test
+    void negatesWithTheSameCurrency() {
+        assertEquals(new Money(new BigDecimal("-12.50"), CZK), new Money(new BigDecimal("12.5"), CZK).negate());
+    }
+
+    @Test
+    void aCurrencyWithoutMinorDigitsKeepsTheAmountAsWritten() {
+        // XXX has getDefaultFractionDigits() == -1, which would otherwise be a negative scale.
+        var none = Currency.getInstance("XXX");
+        assertEquals(new BigDecimal("12.5"), new Money(new BigDecimal("12.50"), none).amount());
+        assertEquals(new BigDecimal("100"), new Money(new BigDecimal("100"), none).amount());
+    }
+
     @Test
     void printsAsAnAmountAndACode() {
         assertEquals("1234.10 CZK", new Money(new BigDecimal("1234.1"), CZK).toString());

testing/kotlin/src/test/kotlin/example/kotlin/KotlinCallerTest.kt

@@ -41,6 +41,18 @@ class KotlinCallerTest {
         assertTrue(errors.isNotEmpty(), "iban read as non-null compiled, so Kotlin sees it as a platform type")
     }
 
+    @Test
+    fun aLookupThatMayFindNothingIsHandledWithAnElvis() {
+        val source = "fun f(me: cz.insuit.moneta.AccountHolder): String = me.accountByIban(\"x\")?.id ?: \"none\""
+        assertEquals(listOf<String>(), compile(source))
+    }
+
+    @Test
+    fun aLookupThatMayFindNothingCannotBeReadAsNonNull() {
+        val errors = compile("fun f(me: cz.insuit.moneta.AccountHolder): String = me.accountByIban(\"x\").id")
+        assertTrue(errors.isNotEmpty(), "accountByIban read as non-null compiled, so its @Nullable is lost")
+    }
+
     /** The errors compiling [source] against the library gives, empty when it compiles. */
     private fun compile(source: String): List<String> {
         val dir = createTempDirectory()