Add basic end-to-end splice tests

lightning/src/ln/channel.rs

@@ -6130,8 +6130,6 @@ where
 				holder_commitment_transaction_number,
 				self.counterparty_next_commitment_transaction_number,
 			);
-			// TODO(splicing) Forced error, as the use case is not complete
-			return Err(AbortReason::InternalError("Splicing not yet supported"));
 		} else {
 			self.assert_no_commitment_advancement(holder_commitment_transaction_number, "initial commitment_signed");
 			self.channel_state = ChannelState::FundingNegotiated(FundingNegotiatedFlags::new());

lightning/src/ln/functional_test_utils.rs

@@ -409,7 +409,7 @@ pub fn provide_anchor_reserves<'a, 'b, 'c>(nodes: &[Node<'a, 'b, 'c>]) -> Transa
 	}
 	let tx = Transaction {
 		version: TxVersion::TWO,
-		lock_time: LockTime::ZERO,
+		lock_time: LockTime::from_height(nodes[0].best_block_info().1).unwrap(),
 		input: vec![TxIn { ..Default::default() }],
 		output,
 	};

lightning/src/ln/funding.rs

@@ -17,6 +17,7 @@ use crate::prelude::Vec;
 use crate::sign::{P2TR_KEY_PATH_WITNESS_WEIGHT, P2WPKH_WITNESS_WEIGHT};
 
 /// The components of a splice's funding transaction that are contributed by one party.
+#[derive(Debug, Clone)]
 pub enum SpliceContribution {
 	/// When funds are added to a channel.
 	SpliceIn {
@@ -85,7 +86,7 @@ impl SpliceContribution {
 
 /// An input to contribute to a channel's funding transaction either when using the v2 channel
 /// establishment protocol or when splicing.
-#[derive(Clone)]
+#[derive(Debug, Clone)]
 pub struct FundingTxInput {
 	/// The unspent [`TxOut`] that the input spends.
 	///