feat: currency id verification (#39)

* feat: currency id verification

Audit specification:
  - Add check of id != 0 in add_currency

* fix: test tag missing

---------

Co-authored-by: 0xevolve <Artevolve@yahoo.com>

src/oracle/oracle.cairo

@@ -1340,6 +1340,7 @@ mod Oracle {
         // @param new_currency: the new currency to be added 
         fn add_currency(ref self: ContractState, new_currency: Currency) {
             self.assert_only_admin();
+            assert(new_currency.id != 0, 'Currency id cannot be 0');
             let existing_currency = self.oracle_currencies_storage.read(new_currency.id);
             assert(existing_currency.id == 0, 'Currency already exists for key');
             self.emit(Event::SubmittedCurrency(SubmittedCurrency { currency: new_currency }));

src/tests/test_oracle.cairo

@@ -821,6 +821,23 @@ fn test_get_last_checkpoint_before_should_fail_if_timestamp_too_old() {
 }
 
 
+#[test]
+#[should_panic(expected: ('Currency id cannot be 0', 'ENTRYPOINT_FAILED'))]
+#[available_gas(2000000000)]
+fn test_add_currency_should_fail_if_currency_id_null() {
+    let (publisher_registry, oracle) = setup();
+    oracle
+        .add_currency(
+            Currency {
+                id: 0,
+                decimals: 18_u32,
+                is_abstract_currency: false,
+                starknet_address: 0.try_into().unwrap(),
+                ethereum_address: 0.try_into().unwrap(),
+            }
+        );
+}
+
 #[test]
 #[should_panic(expected: ('No base currency registered', 'ENTRYPOINT_FAILED'))]
 #[available_gas(2000000000)]