From 9c6c30028933fe54ce35c7d7847a514c8b7cdd30 Mon Sep 17 00:00:00 2001
From: Ruben de Vries <ruben@rubensayshi.com>
Date: Tue, 8 Apr 2014 10:26:30 +0200
Subject: [PATCH 1/2] fixed calcDifficulty by making sure the MAX_TARGET is
 also locally available. added tests for 2 difficulty calculations.

---
 test/test.util.js | 13 +++++++++++++
 util/util.js      |  2 +-
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/test/test.util.js b/test/test.util.js
index b8c422d..edb1182 100644
--- a/test/test.util.js
+++ b/test/test.util.js
@@ -187,4 +187,17 @@ describe('util', function() {
       });
     });
   });
+  describe('#calcDifficulty', function() {
+    var bitsgenesis = 486604799;
+    it('should work for ' + bitsgenesis, function() {
+      var difficulty = coinUtil.calcDifficulty(bitsgenesis);
+      difficulty.should.equal(1);
+    });
+    var bitslater = 419476394;
+    it('should work for ' + bitslater, function() {
+      var difficulty = coinUtil.calcDifficulty(bitslater);
+      difficulty.should.equal(6119726089);
+    });
+  });
+
 });
diff --git a/util/util.js b/util/util.js
index eec49b2..f89dce8 100644
--- a/util/util.js
+++ b/util/util.js
@@ -510,4 +510,4 @@ exports.INT64_MAX = INT64_MAX;
 // makes 1 BTC
 exports.COIN = 100000000;
 
-exports.MAX_TARGET = new Buffer('00000000FFFF0000000000000000000000000000000000000000000000000000', 'hex');
+var MAX_TARGET = exports.MAX_TARGET = new Buffer('00000000FFFF0000000000000000000000000000000000000000000000000000', 'hex');

From 3118ab1d0c1337a669ca248982b04b008dd24613 Mon Sep 17 00:00:00 2001
From: Ruben de Vries <ruben@rubensayshi.com>
Date: Tue, 8 Apr 2014 16:08:16 +0200
Subject: [PATCH 2/2] updated the calcDifficulty test to make it clear with
 what we're testing

---
 test/test.util.js | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/test/test.util.js b/test/test.util.js
index edb1182..22180ff 100644
--- a/test/test.util.js
+++ b/test/test.util.js
@@ -189,13 +189,13 @@ describe('util', function() {
   });
   describe('#calcDifficulty', function() {
     var bitsgenesis = 486604799;
-    it('should work for ' + bitsgenesis, function() {
+    it('should work for the bits from the genesis block; ' + bitsgenesis, function() {
       var difficulty = coinUtil.calcDifficulty(bitsgenesis);
       difficulty.should.equal(1);
     });
-    var bitslater = 419476394;
-    it('should work for ' + bitslater, function() {
-      var difficulty = coinUtil.calcDifficulty(bitslater);
+    var randomotherbits = 419476394;
+    it('should work for the bits in a randomly chosen block, eg [00000000000000001fef2bbc6da9b65e16f9187b7d88f15a308490bf2c9b8e1d] ' + randomotherbits, function() {
+      var difficulty = coinUtil.calcDifficulty(randomotherbits);
       difficulty.should.equal(6119726089);
     });
   });