Merge #95: Remove inner checksum in pegin descriptor

fe43086 remove inner checksum in pegin desc and fix test (Riccardo Casatta)
1a0fa05 expand pegin test to show inner checksum (Riccardo Casatta)

Pull request description:

  I noticed in the pegin descriptor inner checksum are printed, for example:

  `pegin(feddesc#cheksum, elem_desc#cheksum)#checksum`

  and this changes it to

  `pegin(feddesc, elem_desc)#checksum`

ACKs for top commit:
  apoelstra:
    ACK fe43086; successfully ran local tests

Tree-SHA512: 59c411c4ec17b71a244a92e73fd9f1938bda68df5e7fff5211055065c66b336b65ea2aea35ae1437a41ab90678f9ed6d8646ca01e229f2f10d39771ce01877e8

src/descriptor/pegin/dynafed_pegin.rs

@@ -71,7 +71,7 @@ impl<Pk: MiniscriptKey> fmt::Display for Pegin<Pk> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         use fmt::Write;
         let mut wrapped_f = checksum::Formatter::new(f);
-        write!(wrapped_f, "pegin({},{})", self.fed_desc, self.elem_desc)?;
+        write!(wrapped_f, "pegin({:#},{:#})", self.fed_desc, self.elem_desc)?;
         wrapped_f.write_checksum_if_not_alt()
     }
 }
@@ -311,7 +311,8 @@ where
 mod tests {
     use elements::hex::FromHex;
 
-    use crate::BtcDescriptor;
+    use crate::descriptor::pegin::Pegin;
+    use crate::{BtcDescriptor, ConfidentialDescriptor, DescriptorPublicKey};
 
     // test vector created with:
     // ```
@@ -352,5 +353,13 @@ mod tests {
         let s = super::bitcoin_witness_script(&d, &claimscript, &secp).unwrap();
         let b = bitcoin::Address::p2wsh(&s, bitcoin::Network::Bitcoin);
         assert_eq!(mainchain_address, b.to_string());
+
+        let elem_desc = "ct(slip77(ab5824f4477b4ebb00a132adfd8eb0b7935cf24f6ac151add5d1913db374ce92),elwpkh([759db348/84'/1'/0']tpubDCRMaF33e44pcJj534LXVhFbHibPbJ5vuLhSSPFAw57kYURv4tzXFL6LSnd78bkjqdmE3USedkbpXJUPA1tdzKfuYSL7PianceqAhwL2UkA/0/*))";
+        let elem_desc: ConfidentialDescriptor<DescriptorPublicKey> = elem_desc.parse().unwrap();
+        let elem_desc = elem_desc.descriptor.at_derivation_index(0).unwrap();
+        let elem_desc = elem_desc.derived_descriptor(&secp).unwrap();
+        let pegin = Pegin::new(d.clone(), elem_desc);
+
+        assert_eq!(pegin.to_string(), "pegin(wsh(or_d(multi(11,020e0338c96a8870479f2396c373cc7696ba124e8635d41b0ea581112b67817261,02675333a4e4b8fb51d9d4e22fa5a8eaced3fdac8a8cbf9be8c030f75712e6af99,02896807d54bc55c24981f24a453c60ad3e8993d693732288068a23df3d9f50d48,029e51a5ef5db3137051de8323b001749932f2ff0d34c82e96a2c2461de96ae56c,02a4e1a9638d46923272c266631d94d36bdb03a64ee0e14c7518e49d2f29bc4010,031c41fdbcebe17bec8d49816e00ca1b5ac34766b91c9f2ac37d39c63e5e008afb,03079e252e85abffd3c401a69b087e590a9b86f33f574f08129ccbd3521ecf516b,03111cf405b627e22135b3b3733a4a34aa5723fb0f58379a16d32861bf576b0ec2,0318f331b3e5d38156da6633b31929c5b220349859cc9ca3d33fb4e68aa0840174,03230dae6b4ac93480aeab26d000841298e3b8f6157028e47b0897c1e025165de1,035abff4281ff00660f99ab27bb53e6b33689c2cd8dcd364bc3c90ca5aea0d71a6,03bd45cddfacf2083b14310ae4a84e25de61e451637346325222747b157446614c,03cc297026b06c71cbfa52089149157b5ff23de027ac5ab781800a578192d17546,03d3bde5d63bdb3a6379b461be64dad45eabff42f758543a9645afd42f6d424828,03ed1e8d5109c9ed66f7941bc53cc71137baa76d50d274bda8d5e8ffbd6e61fe9a),and_v(v:older(4032),multi(2,03aab896d53a8e7d6433137bbba940f9c521e085dd07e60994579b64a6d992cf79,0291b7d0b1b692f8f524516ed950872e5da10fb1b808b5a526dedc6fed1cf29807,0386aa9372fbab374593466bc5451dc59954e90787f08060964d95c87ef34ca5bb)))),elwpkh(0321da398ca2ddc09be89caa26e6730ae84751b6ea3a1ca46aa365bb5e1c3d9620))#qp4fan9q");
     }
 }