Simple off-chain future soft fork aware testing framework in go

These tools are crucial for testing new protocols and features like statechains, vaults, and channel constructions under realistic conditions. A typical process includes setting up a Bitcoin daemon in regtest mode, manipulating it via bitcoin-cli or custom JSON-RPC calls, and testing the protocol designed against this setup. However, there has been a lack of streamlined tools comparable to those available for Ethereum, such as anvil, which provides a local test node that is quick to start and easy to integrate with the necessary chain features.

Addressing this gap, a new tool has been developed specifically for Bitcoin, enabling developers to prototype functionalities like CTV (CHECKTEMPLATEVERIFY), APO (Assume UTXO), CAT, CSFS, and INTERNALKEY without resorting to mock implementations. This tool is accessible via a GitHub repository at go-regtest. The primary advantage of this new library is its ability to simplify the development process by automatically detecting and interfacing with either a specialized version of bitcoind (bitcoind-inquisition) or the standard version, depending on what is available. This feature is particularly beneficial for continuous integration setups and for libraries needing to test subsets of features that become available on local chains post-activation.

The go-regtest library allows for dynamic testing environments where features like CTV can be live-tested within the development of statechain implementations. For instance, developers can verify withdrawal templates directly against a CTV-active node before finalizing their designs. Similarly, vault prototypes can utilize APO-based recovery paths with actual signature verifications rather than relying on simulated data. This approach not only enhances the reliability of the testing but also ensures that the development harness remains non-intrusive, allowing developers to focus more on the actual testing of their code.

The library is still in its developmental stages, marked as pre-1.0 and licensed under MIT. It does not require Docker, aiming for simplicity and ease of use. Additional resources, including a cmake recipe for Inquisition and a troubleshooting guide, are provided in the README file to help developers navigate common issues encountered during setup and use. This initiative significantly contributes to the Bitcoin development ecosystem by providing a robust framework for testing and validating new blockchain features efficiently.