Add RLP encoding for CrosslinkRecord

src/state/crosslink_record.rs

@@ -1,4 +1,5 @@
 use super::utils::types::Sha256Digest;
+use super::rlp::{ RlpStream, Encodable };
 
 pub struct CrosslinkRecord {
     pub epoch: u64,
@@ -14,8 +15,19 @@ impl CrosslinkRecord {
     }
 }
 
+/*
+ * RLP Encoding
+ */
+impl Encodable for CrosslinkRecord {
+    fn rlp_append(&self, s: &mut RlpStream) {
+        s.append(&self.epoch);
+        s.append(&self.hash);
+    }
+}
+
 #[cfg(test)]
 mod tests {
+    use super::super::rlp;
     use super::*;
 
     #[test]
@@ -26,4 +38,17 @@ mod tests {
         assert_eq!(c.epoch, epoch);
         assert_eq!(c.hash, hash);
     }
+
+    #[test]
+    fn test_serialization() {
+        let c = CrosslinkRecord {
+            epoch: 100,
+            hash: Sha256Digest::zero()
+        };
+        let e = rlp::encode(&c);
+        assert_eq!(e.len(), 34);
+        assert_eq!(e[0], 100);
+        assert_eq!(e[1], 160);
+        assert_eq!(e[2..34], [0; 32]);
+    }
 }