eth-tester

from eth_tester import EthereumTester, MockBackend from eth_utils import encode_hex, decode_hex # 1. Initialize the EthereumTester with a MockBackend # The MockBackend is a simple in-memory backend provided by eth-tester. # It simulates basic blockchain interactions for testing purposes. # For a full EVM, install with 'pip install eth-tester[py-evm]' and use PyEVMBackend. tester = EthereumTester(backend=MockBackend()) print("EthereumTester initialized with MockBackend.") # 2. Get available accounts accounts = tester.get_accounts() print(f"Available accounts: {[encode_hex(acc) for acc in accounts]}") # 3. Mine a block # Many operations, especially transactions, only take effect after a block is mined. tester.mine_block() print(f"Block mined. Current block number: {tester.get_block_by_number('latest')['number']}") # 4. Get an account's balance # In MockBackend, accounts start with a default balance. account_0_address = accounts[0] balance = tester.get_balance(account_0_address) print(f"Balance of {encode_hex(account_0_address)}: {balance} wei") # 5. Send a simple 'transaction' (e.g., a call) which is processed after mining. # Note: MockBackend does not simulate value transfer or EVM state changes without a full EVM backend. # This example primarily demonstrates the API for sending a transaction. transaction_hash = tester.send_transaction({ 'from': account_0_address, 'to': accounts[1], # Sending to another account (conceptual in MockBackend) 'gas_price': 0, 'gas': 21000, 'value': 0, 'data': b'' }) print(f"Transaction sent (hash: {encode_hex(transaction_hash)})") # Mine another block for the transaction to be included tester.mine_block() print(f"Block mined. Current block number: {tester.get_block_by_number('latest')['number']}")