do not print parsed_result in invalid test

src/proto.rs

@@ -125,7 +125,7 @@ impl From<bool> for DNSMessageType {
     }
 }
 
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, PartialEq)]
 pub struct DNSHeader {
     /// used by the requester to match up replies to outstanding queries
     pub id: u16,
@@ -317,15 +317,13 @@ mod tests {
             dns_query[3] = (rcode as u8) << 0;
 
             let parse_result = DNSHeader::from_udp_datagram(&dns_query);
-            let parse_result_clone = parse_result.clone();
 
             assert_eq!(
-                parse_result.err(),
-                Some(DNSParseError::DNSRCodeInvalid),
-                "query: {:02x?}, rcode: {}, parsed_rcode: {:?}",
+                parse_result,
+                Err(DNSParseError::DNSRCodeInvalid),
+                "query: {:02x?}, rcode: {}",
                 dns_query,
                 rcode,
-                parse_result_clone.map(|x| x.response_code).unwrap()
             );
         }
     }