Implement custom Debug for Magic types

Related to #63

zebra-network/Cargo.toml

@@ -9,16 +9,19 @@ edition = "2018"
 
 [dependencies]
 bitflags = "1.2"
-bytes = "0.4"
-rand = "0.7"
 byteorder = "1.3"
+bytes = "0.4"
 chrono = "0.4"
 thiserror = "1"
 serde = { version = "1", features = ["serde_derive"] }
 pin-project = "0.4"
-# indexmap has rayon support for parallel iteration, 
+hex = "0.4"
+# indexmap has rayon support for parallel iteration,
 # which we don't use, so disable it to drop the dependencies.
 indexmap = { version = "1.2", default-features = false }
+pin-project = "0.4"
+rand = "0.7"
+serde = { version = "1", features = ["serde_derive"] }
 
 tokio = "=0.2.0-alpha.6"
 futures-preview = "=0.3.0-alpha.19"

zebra-network/src/protocol/types.rs

@@ -1,9 +1,18 @@
 //! Newtype wrappers assigning semantic meaning to primitive types.
 
+use hex;
+use std::fmt;
+
 /// A magic number identifying the network.
-#[derive(Copy, Clone, Debug, Eq, PartialEq)]
+#[derive(Copy, Clone, Eq, PartialEq)]
 pub struct Magic(pub [u8; 4]);
 
+impl fmt::Debug for Magic {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        f.debug_tuple("Magic").field(&hex::encode(&self.0)).finish()
+    }
+}
+
 /// A protocol version number.
 #[derive(Copy, Clone, Debug, Eq, PartialEq)]
 pub struct Version(pub u32);
@@ -34,3 +43,15 @@ impl Default for Nonce {
         Self(thread_rng().gen())
     }
 }
+
+#[cfg(test)]
+mod tests {
+
+    use crate::constants::magics;
+
+    #[test]
+    fn magic_debug() {
+        assert_eq!(format!("{:?}", magics::MAINNET), "Magic(\"24e92764\")");
+        assert_eq!(format!("{:?}", magics::TESTNET), "Magic(\"fa1af9bf\")");
+    }
+}