feat(txn_utils): add custom nonce support

[sebsadface]

Summary

This PR adds support for custom nonce management in the transaction utilities, allowing users to optionally specify a nonce value via the tx_options parameter. The implementation maintains full backward compatibility by automatically fetching the nonce from the blockchain when not provided, while adding proper validation to ensure nonce values are non-negative integers.

Changes

• Modified build_and_send_transaction() to accept optional nonce in tx_options
• Added validation to ensure nonce is a non-negative integer
• Falls back to web3.eth.get_transaction_count() when nonce not provided
• Added tests for transaction_utils

Use Cases

This change enables:

• Transaction replacement: Reuse same nonce with higher gas price
• Gap filling: Resubmit failed transactions with specific nonces
• High-throughput apps: Manual nonce management for parallel transactions (poseidon)

Testing

All 11 unit tests pass covering:

• Custom nonce usage
• Automatic nonce fetching
• Validation of invalid inputs (negative, string, float, None)
• Edge cases (zero, large values)
• Integration with other tx options

Example Usage

# Custom nonce
tx_options = {"nonce": 42}
build_and_send_transaction(web3, account, client_func, tx_options=tx_options)

# Automatic (existing behavior)
build_and_send_transaction(web3, account, client_func)

[bonnie57]

Could you add an integration test to ensure everything is working correctly?

[sebsadface]

> Could you add an integration test to ensure everything is working correctly?

added in 8915cd6

[bonnie57]

LGTM

Minor thing: The integration tests don't need the story_client object. Please remove the story_client argument and fixture.

[sebsadface]

LGTM

Minor thing: The integration tests don't need the story_client object. Please remove the story_client argument and fixture.

Good catch, resolved in 28ac44a