f use helper

Author: TheBlueMatt

lightning/src/ln/functional_tests.rs

@@ -610,7 +610,7 @@ fn test_update_fee_that_funder_cannot_afford() {
 
 		//We made sure neither party's funds are below the dust limit and there are no HTLCs here
 		assert_eq!(commitment_tx.output.len(), 2);
-		let total_fee: u64 = feerate as u64 * COMMITMENT_TX_BASE_WEIGHT / 1000;
+		let total_fee: u64 = commit_tx_fee_msat(feerate, 0) / 1000;
 		let mut actual_fee = commitment_tx.output.iter().fold(0, |acc, output| acc + output.value);
 		actual_fee = channel_value - actual_fee;
 		assert_eq!(total_fee, actual_fee);