provide a new_unspendable implementation for provided verifiers

Author: JoshOrndorff

tuxedo-core/src/verifier.rs

@@ -76,6 +76,10 @@ impl Verifier for Unspendable {
     fn verify(&self, _simplified_tx: &[u8], _: u32, _: &()) -> bool {
         false
     }
+
+    fn new_unspendable() -> Option<Self> {
+        Some(Self)
+    }
 }
 
 // Idea: It could be useful to allow delay deciding whether the redemption should succeed
@@ -96,6 +100,10 @@ impl Verifier for TestVerifier {
     fn verify(&self, _simplified_tx: &[u8], _: u32, _: &()) -> bool {
         self.verifies
     }
+
+    fn new_unspendable() -> Option<Self> {
+        Some(Self { verifies: false })
+    }
 }
 
 #[cfg(test)]

tuxedo-core/src/verifier/multi_signature.rs

@@ -96,6 +96,13 @@ impl Verifier for ThresholdMultiSignature {
 
         valid_sigs.len() >= self.threshold.into()
     }
+
+    fn new_unspendable() -> Option<Self> {
+        Some(Self {
+            threshold: 1,
+            signatories: Vec::new(),
+        })
+    }
 }
 
 #[cfg(test)]

tuxedo-core/src/verifier/simple_signature.rs

@@ -49,6 +49,10 @@ impl Verifier for Sr25519Signature {
     fn verify(&self, simplified_tx: &[u8], _: u32, sig: &Signature) -> bool {
         sp_io::crypto::sr25519_verify(sig, simplified_tx, &Public::from_h256(self.owner_pubkey))
     }
+
+    fn new_unspendable() -> Option<Self> {
+        Some(Self::new(H256::zero()))
+    }
 }
 
 /// Pay To Public Key Hash (P2PKH)
@@ -70,6 +74,12 @@ impl Verifier for P2PKH {
         BlakeTwo256::hash(pubkey) == self.owner_pubkey_hash
             && sp_io::crypto::sr25519_verify(signature, simplified_tx, pubkey)
     }
+
+    fn new_unspendable() -> Option<Self> {
+        Some(Self {
+            owner_pubkey_hash: H256::zero(),
+        })
+    }
 }
 
 #[cfg(test)]