Add default trait implementation for TxIn

src/blockdata/transaction.rs

@@ -204,6 +204,17 @@ pub struct TxIn {
 }
 serde_struct_impl!(TxIn, previous_output, script_sig, sequence, witness);
 
+impl Default for TxIn {
+    fn default() -> TxIn {
+        TxIn {
+            previous_output: OutPoint::default(),
+            script_sig: Script::new(),
+            sequence: u32::max_value(),
+            witness: Vec::new(),
+        }
+    }
+}
+
 /// A transaction output, which defines new coins to be created from old ones.
 #[derive(Clone, PartialEq, Eq, Debug, Hash)]
 pub struct TxOut {
@@ -662,6 +673,16 @@ mod tests {
         assert!(txin.is_ok());
     }
 
+    #[test]
+    fn test_txin_default() {
+        let txin = TxIn::default();
+        assert_eq!(txin.previous_output, OutPoint::default());
+        assert_eq!(txin.script_sig, Script::new());
+        assert_eq!(txin.sequence, 0xFFFFFFFF);
+        assert_eq!(txin.previous_output, OutPoint::default());
+        assert_eq!(txin.witness.len(), 0 as usize);
+    }
+
     #[test]
     fn test_is_coinbase () {
         use network::constants::Network;