feat: panic if amount is zero

packages/usdc_migration/src/errors.cairo

@@ -1,3 +1,4 @@
 pub mod Errors {
     pub const THRESHOLD_TOO_SMALL: felt252 = 'Threshold is too small';
+    pub const AMOUNT_IS_ZERO: felt252 = 'Amount is zero';
 }

packages/usdc_migration/src/tests/test_usdc_migration.cairo

@@ -226,6 +226,11 @@ fn test_swap_to_new_assertions() {
     cheat_caller_address_once(contract_address: cfg.usdc_migration_contract, caller_address: user);
     let res = usdc_migration_safe_dispatcher.swap_to_new(:amount);
     assert_panic_with_error(res, Erc20Error::INSUFFICIENT_BALANCE.describe());
+
+    // Amount is zero.
+    cheat_caller_address_once(contract_address: cfg.usdc_migration_contract, caller_address: user);
+    let res = usdc_migration_safe_dispatcher.swap_to_new(amount: Zero::zero());
+    assert_panic_with_felt_error(res, Errors::AMOUNT_IS_ZERO);
 }
 
 #[test]
@@ -350,4 +355,9 @@ fn test_swap_to_legacy_assertions() {
     cheat_caller_address_once(contract_address: cfg.usdc_migration_contract, caller_address: user);
     let res = usdc_migration_safe_dispatcher.swap_to_legacy(:amount);
     assert_panic_with_error(res, Erc20Error::INSUFFICIENT_BALANCE.describe());
+
+    // Amount is zero.
+    cheat_caller_address_once(contract_address: cfg.usdc_migration_contract, caller_address: user);
+    let res = usdc_migration_safe_dispatcher.swap_to_legacy(amount: Zero::zero());
+    assert_panic_with_felt_error(res, Errors::AMOUNT_IS_ZERO);
 }

packages/usdc_migration/src/usdc_migration.cairo

@@ -160,6 +160,7 @@ pub mod USDCMigration {
             to_token: IERC20Dispatcher,
             amount: u256,
         ) {
+            assert(amount > 0, Errors::AMOUNT_IS_ZERO);
             let contract_address = get_contract_address();
             let user = get_caller_address();
             from_token.checked_transfer_from(sender: user, recipient: contract_address, :amount);