Add tests to lib

src/lib.rs

@@ -110,6 +110,7 @@ mod tests {
     use super::*;
     use bitcoin::{Amount, ScriptBuf, TxOut, Weight};
     use bitcoin::transaction::effective_value;
+    use std::iter::zip;
 
     use arbitrary::{Arbitrary, Result, Unstructured};
     use arbtest::arbtest;
@@ -123,6 +124,43 @@ mod tests {
         Utxo { output, satisfaction_weight }
     }
 
+    pub fn build_pool() -> Vec<Utxo> {
+        let amts = [
+            27336,
+            238,
+            9225,
+            20540,
+            35590,
+            49463,
+            6331,
+            35548,
+            50363,
+            28009,
+        ];
+
+        let weights = [
+            25350,
+            106,
+            3311,
+            2633,
+            21081,
+            35260,
+            3896,
+            6377,
+            6851,
+            20236
+        ];
+
+        let utxos: Vec<_> = zip(amts, weights)
+            .map(|(a, w)| {
+                let amt = Amount::from_sat(a);
+                let weight = Weight::from_wu(w);
+                build_utxo(amt, weight)
+            }).collect();
+
+        utxos
+    }
+
     #[derive(Debug, Clone, PartialEq, Ord, Eq, PartialOrd, Arbitrary)]
     pub struct Utxo {
         output: TxOut,
@@ -164,69 +202,74 @@ mod tests {
         }
     }
 
-    use std::iter::zip;
     #[test]
     fn select_coins_no_solution() {
         let target = Amount::from_sat(255432);
         let cost_of_change = Amount::ZERO;
         let fee_rate = FeeRate::ZERO;
         let lt_fee_rate = FeeRate::ZERO;
+        let pool = build_pool();
 
-        let amts = [
-            27336,
-            238,
-            9225,
-            20540,
-            35590,
-            49463,
-            6331,
-            35548,
-            50363,
-            28009,
-        ];
+        let result = select_coins(
+            target,
+            cost_of_change,
+            fee_rate,
+            lt_fee_rate,
+            &pool,
+        );
 
-        let weights = [
-            25350,
-            106,
-            3311,
-            2633,
-            21081,
-            35260,
-            3896,
-            6377,
-            6851,
-            20236
-        ];
+        // This yields no solution because:
+        //  * BnB fails because the sum overage is greater than ost_of_change
+        //  * SRD fails because the sum is greater the utxo sum + CHANGE_LOWER
+        assert!(result.is_none());
+    }
 
-        let utxos: Vec<_> = zip(amts, weights)
-            .map(|(a, w)| {
-                let amt = Amount::from_sat(a);
-                let tx_out = TxOut {
-                    value: amt,
-                    script_pubkey: vec![].into()
-                };
-                let weight = Weight::from_wu(w);
+    #[test]
+    fn select_coins_srd_solution() {
+        let target = Amount::from_sat(255432) - CHANGE_LOWER;
+        let cost_of_change = Amount::ZERO;
+        let fee_rate = FeeRate::ZERO;
+        let lt_fee_rate = FeeRate::ZERO;
+        let pool = build_pool();
+
+        let result = select_coins(
+            target,
+            cost_of_change,
+            fee_rate,
+            lt_fee_rate,
+            &pool,
+        );
 
-                let u = Utxo {
-                    output: tx_out,
-                    satisfaction_weight: weight
-                };
+        assert!(result.is_some());
+        let result: Amount = result.unwrap().map(|u| u.value()).sum();
+        assert!(result > target);
+    }
 
-                u
-            }).collect();
+    #[test]
+    fn select_coins_bnb_solution() {
+        let target = Amount::from_sat(255432);
+        let fee_rate = FeeRate::ZERO;
+        let lt_fee_rate = FeeRate::ZERO;
+        let pool = build_pool();
+
+        // set cost_of_change to be the differene
+        // between the total pool sum and the target amount
+        // plus 1.  This creates an upper bound that the sum
+        // of all utxos will fall bellow resulting in a BnB match.
+        let cost_of_change = Amount::from_sat(7211);
 
         let result = select_coins(
             target,
             cost_of_change,
             fee_rate,
             lt_fee_rate,
-            &utxos,
+            &pool,
         );
 
-        // This yields no solution because:
-        //  * BnB fails because the sum overage is greater than ost_of_change
-        //  * SRD fails because the sum is greater the utxo sum + CHANGE_LOWER
-        assert!(result.is_none());
+        assert!(result.is_some());
+        let result: Amount = result.unwrap().map(|u| u.value()).sum();
+        assert!(result > target);
+        assert!(result <= target + cost_of_change);
     }
 
     #[test]