fix: transfer amount less than or equal to the balance. (#36)

* fix:  transfer amount less than or equal to the balance.

* feat: perform a test to ensure the balance is sufficient for the full amount.

* feat: fix code style

Author: riflecode

cdp/wallet_address.py

@@ -336,7 +336,7 @@ def _ensure_sufficient_balance(self, amount: Decimal, asset_id: str) -> None:
         """
         current_balance = self.balance(asset_id)
 
-        if amount < current_balance:
+        if amount <= current_balance:
             return
 
         raise InsufficientFundsError(expected=amount, exact=current_balance)

tests/test_wallet_address.py

@@ -999,3 +999,24 @@ def test_deploy_multi_token_broadcast_api_error(mock_smart_contract, wallet_addr
     mock_smart_contract.create.assert_called_once()
     mock_smart_contract_instance.sign.assert_called_once_with(wallet_address_with_key.key)
     mock_smart_contract_instance.broadcast.assert_called_once()
+
+
+@patch("cdp.Cdp.api_clients")
+def test_ensure_sufficient_balance_sufficient_full_amount(
+    mock_api_clients, wallet_address_factory, balance_model_factory
+):
+    """Test the ensure_sufficient_balance method with sufficient full amount balance."""
+    wallet_address = wallet_address_factory()
+    balance_model = balance_model_factory(
+        amount="1500000000000000000", network_id="base-sepolia", asset_id="eth", decimals=18
+    )
+
+    mock_get_balance = Mock()
+    mock_get_balance.return_value = balance_model
+    mock_api_clients.external_addresses.get_external_address_balance = mock_get_balance
+
+    wallet_address._ensure_sufficient_balance(Decimal("1.5"), "eth")
+
+    mock_get_balance.assert_called_once_with(
+        network_id=wallet_address.network_id, address_id=wallet_address.address_id, asset_id="eth"
+    )