From f21e2439be8f9c8c4310d67c2425151a3bc327d2 Mon Sep 17 00:00:00 2001
From: Braydon Fuller <braydon@bitpay.com>
Date: Tue, 31 Mar 2015 18:50:36 -0400
Subject: [PATCH] Added preconditions to the Headers message.

---
 lib/messages/commands/headers.js |  5 +++++
 test/messages/commands/index.js  | 31 +++++++++++++++++++++++++++++++
 2 files changed, 36 insertions(+)

diff --git a/lib/messages/commands/headers.js b/lib/messages/commands/headers.js
index 5fe1207..14d600e 100644
--- a/lib/messages/commands/headers.js
+++ b/lib/messages/commands/headers.js
@@ -6,6 +6,7 @@ var bitcore = require('bitcore');
 var utils = require('../utils');
 var BufferReader = bitcore.encoding.BufferReader;
 var BufferWriter = bitcore.encoding.BufferWriter;
+var _ = bitcore.deps._;
 var $ = bitcore.util.preconditions;
 
 /**
@@ -24,6 +25,10 @@ function HeadersMessage(arg, options) {
   this.BlockHeader = options.BlockHeader;
   this.magicNumber = options.magicNumber;
   this.command = 'headers';
+  $.checkArgument(
+    _.isUndefined(arg) || (Array.isArray(arg) && arg[0] instanceof this.BlockHeader),
+    'First argument is expected to be an array of BlockHeader instances'
+  );
   this.headers = arg;
 }
 inherits(HeadersMessage, Message);
diff --git a/test/messages/commands/index.js b/test/messages/commands/index.js
index 84df325..ed28719 100644
--- a/test/messages/commands/index.js
+++ b/test/messages/commands/index.js
@@ -10,6 +10,19 @@ describe('Command Messages', function() {
 
   var messages = new Messages();
 
+  describe('Alert', function() {
+
+    it('should accept a transaction instance as an argument', function() {
+      var message = messages.Alert({
+        payload: new Buffer('abcdef', 'hex'),
+        signature: new Buffer('123456', 'hex')
+      });
+      message.payload.should.deep.equal(new Buffer('abcdef', 'hex'));
+      message.signature.should.deep.equal(new Buffer('123456', 'hex'));
+    });
+
+  });
+
   describe('Transaction', function() {
 
     it('should accept a transaction instance as an argument', function() {
@@ -123,6 +136,24 @@ describe('Command Messages', function() {
 
   });
 
+  describe('Headers', function() {
+    it('should error if arg is not an array', function() {
+      (function() {
+        var message = messages.Headers({});
+      }).should.throw('First argument is expected to be an array');
+    });
+    it('should error if arg is an empty array', function() {
+      (function() {
+        var message = messages.Headers([]);
+      }).should.throw('First argument is expected to be an array');
+    });
+    it('should error if arg is not an array of BlockHeaders', function() {
+      (function() {
+        var message = messages.Headers([Number(0)]);
+      }).should.throw('First argument is expected to be an array');
+    });
+  });
+
   describe('MerkleBlock', function() {
 
     it('should return null buffer for payload', function() {