Rename and test improvements (review)

Author: optout21

lightning/src/ln/channel.rs

@@ -4473,7 +4473,7 @@ fn get_v2_channel_reserve_satoshis(channel_value_satoshis: u64, dust_limit_satos
 /// input_count: Number of contributed inputs.
 /// witness_weight: The witness weight for contributed inputs.
 #[allow(dead_code)] // TODO(dual_funding): Remove once V2 channels is enabled.
-fn estimate_funding_transaction_fee(
+fn estimate_v2_funding_transaction_fee(
 	is_initiator: bool, input_count: usize, witness_weight: Weight, 
 	funding_feerate_sat_per_1000_weight: u32,
 ) -> u64 {
@@ -4504,7 +4504,7 @@ pub(super) fn calculate_our_funding_satoshis(
 	total_witness_weight: Weight, funding_feerate_sat_per_1000_weight: u32,
 	holder_dust_limit_satoshis: u64,
 ) -> Result<u64, APIError> {
-	let estimated_fee = estimate_funding_transaction_fee(is_initiator, funding_inputs.len(), total_witness_weight, funding_feerate_sat_per_1000_weight);
+	let estimated_fee = estimate_v2_funding_transaction_fee(is_initiator, funding_inputs.len(), total_witness_weight, funding_feerate_sat_per_1000_weight);
 
 	let mut total_input_satoshis = 0u64;
 	for (idx, input) in funding_inputs.iter().enumerate() {
@@ -12253,40 +12253,43 @@ mod tests {
 	}
 
 	#[test]
-	fn test_estimate_funding_transaction_fee() {
-		use crate::ln::channel::estimate_funding_transaction_fee;
+	fn test_estimate_fv2_unding_transaction_fee() {
+		use crate::ln::channel::estimate_v2_funding_transaction_fee;
 		use bitcoin::Weight;
 
-		let witness_weight = Weight::from_wu(300);
-
+		// 2 inputs with weight 300, initiator, 2000 sat/kw feerate
 		assert_eq!(
-			estimate_funding_transaction_fee(true, 2, witness_weight, 2000),
+			estimate_v2_funding_transaction_fee(true, 2, Weight::from_wu(300), 2000),
 			1668
 		);
 
+		// higher feerate
 		assert_eq!(
-			estimate_funding_transaction_fee(true, 2, witness_weight, 3000),
+			estimate_v2_funding_transaction_fee(true, 2, Weight::from_wu(300), 3000),
 			2502
 		);
 
+		// only 1 input
 		assert_eq!(
-			estimate_funding_transaction_fee(true, 1, witness_weight, 2000),
+			estimate_v2_funding_transaction_fee(true, 1, Weight::from_wu(300), 2000),
 			1348
 		);
 
+		// 0 input weight
 		assert_eq!(
-			estimate_funding_transaction_fee(true, 1, Weight::from_wu(0), 2000),
+			estimate_v2_funding_transaction_fee(true, 1, Weight::from_wu(0), 2000),
 			748
 		);
 
+		// not initiator
 		assert_eq!(
-			estimate_funding_transaction_fee(false, 1, Weight::from_wu(0), 2000),
+			estimate_v2_funding_transaction_fee(false, 1, Weight::from_wu(0), 2000),
 			320
 		);
 	}
 
-	fn prepare_input(value: u64) -> (TxIn, TransactionU16LenLimited) {
-		let input_1_prev_out = TxOut { value: Amount::from_sat(value), script_pubkey: ScriptBuf::default() };
+	fn prepare_funding_input(funding_input_sats: u64) -> (TxIn, TransactionU16LenLimited) {
+		let input_1_prev_out = TxOut { value: Amount::from_sat(funding_input_sats), script_pubkey: ScriptBuf::default() };
 		let input_1_prev_tx = Transaction {
 			input: vec![], output: vec![input_1_prev_out],
 			version: Version::TWO, lock_time: bitcoin::absolute::LockTime::ZERO,
@@ -12303,26 +12306,32 @@ mod tests {
 		use crate::ln::channel::calculate_our_funding_satoshis;
 		use bitcoin::Weight;
 
-		let inputs_1 = [
-			prepare_input(20_000),
-		];
-		let inputs_2 = [
-			prepare_input(200_000),
-			prepare_input(100_000),
-		];
-		let witness_weight = Weight::from_wu(300);
-
 		// normal use case, output is less than the available inputs
 		assert_eq!(
-			calculate_our_funding_satoshis(true, &inputs_2, witness_weight, 2000, 1000)
-				.unwrap(),
+			calculate_our_funding_satoshis(
+				true,
+				&[
+					prepare_funding_input(200_000),
+					prepare_funding_input(100_000),
+				],
+				Weight::from_wu(300),
+				2000,
+				1000,
+			).unwrap(),
 			298332
 		);
 
 		// below dust limit
 		assert_eq!(
-			calculate_our_funding_satoshis(true, &inputs_1, witness_weight, 2000, 20_000)
-				.unwrap(),
+			calculate_our_funding_satoshis(
+				true,
+				&[
+					prepare_funding_input(20_000),
+				],
+				Weight::from_wu(300),
+				2000,
+				20_000,
+			).unwrap(),
 			0
 		);
 	}