Refactor: Move TxTemplate types and logic to bdk_testenv (Fixes #1936)

crates/testenv/src/lib.rs

@@ -1,6 +1,7 @@
 #![cfg_attr(coverage_nightly, feature(coverage_attribute))]
 
 pub mod utils;
+pub mod tx_template;
 
 use anyhow::Context;
 use bdk_chain::CheckPoint;

crates/testenv/src/tx_template.rs

@@ -0,0 +1,159 @@
+#![cfg(feature = "miniscript")]
+
+use bdk_testenv::utils::DESCRIPTORS;
+use rand::distributions::{Alphanumeric, DistString};
+use std::collections::HashMap;
+
+use bdk_chain::{spk_txout::SpkTxOutIndex, tx_graph::TxGraph, Anchor, CanonicalizationParams};
+use bitcoin::{
+    locktime::absolute::LockTime, secp256k1::Secp256k1, transaction, Amount, OutPoint, ScriptBuf,
+    Sequence, Transaction, TxIn, TxOut, Txid, Witness,
+};
+use miniscript::Descriptor;
+
+/// Template for creating a transaction in `TxGraph`.
+///
+/// The incentive for transaction templates is to create a transaction history in a simple manner to
+/// avoid having to explicitly hash previous transactions to form previous outpoints of later
+/// transactions.
+#[derive(Clone, Copy, Default)]
+pub struct TxTemplate<'a, A> {
+    /// Uniquely identifies the transaction, before it can have a txid.
+    pub tx_name: &'a str,
+    pub inputs: &'a [TxInTemplate<'a>],
+    pub outputs: &'a [TxOutTemplate],
+    pub anchors: &'a [A],
+    pub last_seen: Option<u64>,
+    pub assume_canonical: bool,
+}
+
+#[allow(dead_code)]
+pub enum TxInTemplate<'a> {
+    /// This will give a random txid and vout.
+    Bogus,
+
+    /// This is used for coinbase transactions because they do not have previous outputs.
+    Coinbase,
+
+    /// Contains the `tx_name` and `vout` that we are spending. The rule is that we must only spend
+    /// from tx of a previous `TxTemplate`.
+    PrevTx(&'a str, usize),
+}
+
+pub struct TxOutTemplate {
+    pub value: u64,
+    pub spk_index: Option<u32>, // some = get spk from SpkTxOutIndex, none = random spk
+}
+
+#[allow(unused)]
+impl TxOutTemplate {
+    pub fn new(value: u64, spk_index: Option<u32>) -> Self {
+        TxOutTemplate { value, spk_index }
+    }
+}
+
+#[allow(dead_code)]
+pub struct TxTemplateEnv<'a, A> {
+    pub tx_graph: TxGraph<A>,
+    pub indexer: SpkTxOutIndex<u32>,
+    pub txid_to_name: HashMap<&'a str, Txid>,
+    pub canonicalization_params: CanonicalizationParams,
+}
+
+#[allow(dead_code)]
+pub fn init_graph<'a, A: Anchor + Clone + 'a>(
+    tx_templates: impl IntoIterator<Item = &'a TxTemplate<'a, A>>,
+) -> TxTemplateEnv<'a, A> {
+    let (descriptor, _) =
+        Descriptor::parse_descriptor(&Secp256k1::signing_only(), DESCRIPTORS[2]).unwrap();
+    let mut tx_graph = TxGraph::<A>::default();
+    let mut indexer = SpkTxOutIndex::default();
+    (0..10).for_each(|index| {
+        indexer.insert_spk(
+            index,
+            descriptor
+                .at_derivation_index(index)
+                .unwrap()
+                .script_pubkey(),
+        );
+    });
+    let mut txid_to_name = HashMap::<&'a str, Txid>::new();
+
+    let mut canonicalization_params = CanonicalizationParams::default();
+    for (bogus_txin_vout, tx_tmp) in tx_templates.into_iter().enumerate() {
+        let tx = Transaction {
+            version: transaction::Version::non_standard(0),
+            lock_time: LockTime::ZERO,
+            input: tx_tmp
+                .inputs
+                .iter()
+                .map(|input| match input {
+                    TxInTemplate::Bogus => TxIn {
+                        previous_output: OutPoint::new(
+                            bitcoin::hashes::Hash::hash(
+                                Alphanumeric
+                                    .sample_string(&mut rand::thread_rng(), 20)
+                                    .as_bytes(),
+                            ),
+                            bogus_txin_vout as u32,
+                        ),
+                        script_sig: ScriptBuf::new(),
+                        sequence: Sequence::default(),
+                        witness: Witness::new(),
+                    },
+                    TxInTemplate::Coinbase => TxIn {
+                        previous_output: OutPoint::null(),
+                        script_sig: ScriptBuf::new(),
+                        sequence: Sequence::MAX,
+                        witness: Witness::new(),
+                    },
+                    TxInTemplate::PrevTx(prev_name, prev_vout) => {
+                        let prev_txid = txid_to_name.get(prev_name).expect(
+                            "txin template must spend from tx of template that comes before",
+                        );
+                        TxIn {
+                            previous_output: OutPoint::new(*prev_txid, *prev_vout as _),
+                            script_sig: ScriptBuf::new(),
+                            sequence: Sequence::default(),
+                            witness: Witness::new(),
+                        }
+                    }
+                })
+                .collect(),
+            output: tx_tmp
+                .outputs
+                .iter()
+                .map(|output| match &output.spk_index {
+                    None => TxOut {
+                        value: Amount::from_sat(output.value),
+                        script_pubkey: ScriptBuf::new(),
+                    },
+                    Some(index) => TxOut {
+                        value: Amount::from_sat(output.value),
+                        script_pubkey: indexer.spk_at_index(index).unwrap(),
+                    },
+                })
+                .collect(),
+        };
+
+        let txid = tx.compute_txid();
+        if tx_tmp.assume_canonical {
+            canonicalization_params.assume_canonical.push(txid);
+        }
+        txid_to_name.insert(tx_tmp.tx_name, txid);
+        indexer.scan(&tx);
+        let _ = tx_graph.insert_tx(tx.clone());
+        for anchor in tx_tmp.anchors.iter() {
+            let _ = tx_graph.insert_anchor(txid, anchor.clone());
+        }
+        if let Some(last_seen) = tx_tmp.last_seen {
+            let _ = tx_graph.insert_seen_at(txid, last_seen);
+        }
+    }
+    TxTemplateEnv {
+        tx_graph,
+        indexer,
+        txid_to_name,
+        canonicalization_params,
+    }
+}