feat: add token approve builder (#180)

Author: alfonsobries

crypto/enums/abi_function.py

@@ -10,3 +10,4 @@ class AbiFunction(Enum):
     VALIDATOR_RESIGNATION = 'resignValidator'
     UPDATE_VALIDATOR = 'updateValidator'
     TRANSFER = 'transfer'
+    APPROVE = 'approve'

crypto/transactions/builder/token_approve_builder.py

@@ -0,0 +1,27 @@
+from crypto.enums.abi_function import AbiFunction
+from crypto.enums.contract_abi_type import ContractAbiType
+from crypto.transactions.builder.abstract_transaction_builder import (
+    AbstractTransactionBuilder,
+)
+from crypto.transactions.types.evm_call import EvmCall
+from crypto.utils.abi_encoder import AbiEncoder
+from crypto.utils.transaction_utils import TransactionUtils
+
+
+class TokenApproveBuilder(AbstractTransactionBuilder):
+    def contract_address(self, address):
+        self.transaction.data['to'] = address
+        return self
+
+    def spender(self, address, amount):
+        encoder = AbiEncoder(ContractAbiType.TOKEN)
+        payload = encoder.encode_function_call(
+            AbiFunction.APPROVE.value, [address, amount]
+        )
+        self.transaction.data['data'] = TransactionUtils.parse_hex_from_str(
+            payload
+        )
+        return self
+
+    def get_transaction_instance(self, data):
+        return EvmCall(data)

tests/fixtures/transactions/token-approve.json

@@ -0,0 +1,16 @@
+{
+	"data": {
+		"value": "0",
+		"senderPublicKey": "0243333347c8cbf4e3cbc7a96964181d02a2b0c854faa2fef86b4b8d92afcf473d",
+		"gasPrice": "5000000000",
+		"gasLimit": "21000",
+		"nonce": "1",
+		"data": "095ea7b30000000000000000000000006f0182a0cc707b055322ccf6d4cb6a5aff1aeb220000000000000000000000000000000000000000000000000000000000000000",
+		"to": "0x6F0182a0cc707b055322CcF6d4CB6a5Aff1aEb22",
+		"v": 0,
+		"r": "f9120b04d549fe3ac691d8ce0cb26a7f104f0686d03434d47528894c0cad1eea",
+		"s": "3a8960d16a4903b52045b1b40b0f81912bc834985fbd80dc75bf7e60b07bb3e1",
+		"hash": "2472dc84d8d4b6fb1d843b1417a14ae8de1865bd86f9cd8b444b7c4ff7c6f28c"
+	},
+	"serialized": "f8ab0185012a05f200825208946f0182a0cc707b055322ccf6d4cb6a5aff1aeb2280b844095ea7b30000000000000000000000006f0182a0cc707b055322ccf6d4cb6a5aff1aeb220000000000000000000000000000000000000000000000000000000000000000825c6ba0f9120b04d549fe3ac691d8ce0cb26a7f104f0686d03434d47528894c0cad1eeaa03a8960d16a4903b52045b1b40b0f81912bc834985fbd80dc75bf7e60b07bb3e1"
+}

tests/transactions/builder/test_token_approve_builder.py

@@ -0,0 +1,53 @@
+from crypto.transactions.builder.token_approve_builder import (
+    TokenApproveBuilder,
+)
+
+
+def test_token_approve_transaction(passphrase, load_transaction_fixture):
+    fixture = load_transaction_fixture('transactions/token-approve')
+
+    builder = (
+        TokenApproveBuilder
+            .new()
+            .spender(fixture['data']['to'], int(fixture['data']['value']))
+            .to(fixture['data']['to'])
+            .nonce(fixture['data']['nonce'])
+            .gas_price(fixture['data']['gasPrice'])
+            .gas_limit(fixture['data']['gasLimit'])
+            .sign(passphrase)
+    )
+
+    assert builder.transaction.data['gasPrice'] == int(
+        fixture['data']['gasPrice']
+    )
+    assert builder.transaction.data['gasLimit'] == int(
+        fixture['data']['gasLimit']
+    )
+    assert builder.transaction.data['nonce'] == fixture['data']['nonce']
+    assert builder.transaction.data['to'].lower() == (
+        fixture['data']['to'].lower()
+    )
+    assert builder.transaction.data['v'] == fixture['data']['v']
+    assert builder.transaction.data['r'] == fixture['data']['r']
+    assert builder.transaction.data['s'] == fixture['data']['s']
+    assert builder.transaction.data['hash'] == fixture['data']['hash']
+
+    assert builder.verify()
+
+
+def test_token_approve_serialization(passphrase, load_transaction_fixture):
+    fixture = load_transaction_fixture('transactions/token-approve')
+
+    builder = (
+        TokenApproveBuilder
+            .new()
+            .spender(fixture['data']['to'], int(fixture['data']['value']))
+            .to(fixture['data']['to'])
+            .nonce(fixture['data']['nonce'])
+            .gas_price(fixture['data']['gasPrice'])
+            .gas_limit(fixture['data']['gasLimit'])
+            .sign(passphrase)
+    )
+
+    serialized = builder.transaction.serialize().hex()
+    assert serialized == fixture['serialized']