Regtest-like mock node interface

[shesek]

bitcoin-mock-rpc is a neat rust library for creating a mock bitcoind-like interface that runs entirely in-process using an SQLite backend.

This can allow testing a complete funding+spending flow directly within Minsc code. The most minimal API necessary to enable this is:

• node::fund(scriptPubKey, amount) -> (txid, vout)
• node::broadcast(tx) -> txid
• node::generate() -> blockhash
• (plus possibly a node() constructor instead of using a singleton)

Qs

• Can be made to work in WASM?
• Possible to connect a block explorer (https://github.com/RCasatta/fbbe)?

Example use:

$alice = tprv8ZgxMBicQKsPfJtqwiW9WhjJHPZtDo8aUbCkkcG8sjHbpZqjghF6ZJ1Tze9fUHrhYyXSNfw5VPbCKEkoFKaDRUzctbSxmxSWNfAGDonxcTG;

$coin = node::fund(wpkh($alice/0), 1.5 BTC);

$psbt = psbt [
  "input": [
    "prevout": $coin,
    "utxo": wpkh($alice/0):1.5 BTC,
  ],
  "output": bcrt1ql8nqx3q3v7napchr6ewy4tpyq5y08ywat84pen:1.499 BTC
];
$signed = psbt::sign($psbt, $alice);
$tx = psbt::extract(psbt::finalize($signed));

$txid = node::broadcast($tx);