Fix bug in rpc error class

Author: Pedro Branco

src/errors/rpc-error.js

@@ -11,7 +11,7 @@ import StandardError from './standard-error';
  */
 
 export default class RpcError extends StandardError {
-  constructor(code, msg, props) {
+  constructor(code, msg, props = {}) {
     if (typeof code != 'number') {
       throw new TypeError(`Non-numeric HTTP code`);
     }
@@ -21,9 +21,9 @@ export default class RpcError extends StandardError {
       msg = null;
     }
 
-    super(msg || STATUS_CODES[code], props);
+    props.code = code;
 
-    this.code = code;
+    super(msg || STATUS_CODES[code], props);
   }
 
   get status() {

test/errors/rpc-error_test.js

@@ -4,6 +4,7 @@
  */
 
 import RpcError from '../../src/errors/rpc-error';
+import { STATUS_CODES } from 'http';
 import should from 'should';
 
 /**
@@ -47,4 +48,10 @@ describe('RpcError', () => {
   it('should return a well-formatted string representation', () => {
     new RpcError(-32601, 'Method not found').toString().should.equal('RpcError: -32601 Method not found');
   });
+
+  it('should return the correct message by its http code', () => {
+    for (const code in STATUS_CODES) {
+      new RpcError(Number(code)).toString().should.equal(`RpcError: ${code} ${STATUS_CODES[code]}`);
+    }
+  });
 });