skip change if it is not above dust threshold

src/wallet.js

@@ -197,7 +197,7 @@ var Wallet = function (seed, options) {
           if(totalInValue < value + fee) continue;
 
           var change = totalInValue - value - fee
-          if(change > 0) {
+          if(change > 0 && !isDust(change)) {
             tx.addOutput(getChangeAddress(), change)
           }
           break;
@@ -210,9 +210,14 @@ var Wallet = function (seed, options) {
         return tx
     }
 
+    this.dustThreshold = 5430
+    function isDust(amount) {
+      return amount <= me.dustThreshold
+    }
+
     function checkDust(value){
-      if (isNullOrUndefined(value) || value < 5430) {
-        throw new Error("Value below dust threshold")
+      if (isNullOrUndefined(value) || isDust(value)) {
+        throw new Error("Value must be above dust threshold")
       }
     }
 

test/wallet.js

@@ -397,7 +397,7 @@ describe('Wallet', function() {
 
       describe('change', function(){
         it('uses the last change address if there is any', function(){
-          var fee = 15000
+          var fee = 5000
           wallet.generateChangeAddress()
           wallet.generateChangeAddress()
           var tx = wallet.createTx(to, value, fee)
@@ -405,11 +405,11 @@ describe('Wallet', function() {
           assert.equal(tx.outs.length, 2)
           var out = tx.outs[1]
           assert.equal(out.address, wallet.changeAddresses[1])
-          assert.equal(out.value, 5000)
+          assert.equal(out.value, 15000)
         })
 
         it('generates a change address if there is not any', function(){
-          var fee = 15000
+          var fee = 5000
           assert.equal(wallet.changeAddresses.length, 0)
 
           var tx = wallet.createTx(to, value, fee)
@@ -417,7 +417,13 @@ describe('Wallet', function() {
           assert.equal(wallet.changeAddresses.length, 1)
           var out = tx.outs[1]
           assert.equal(out.address, wallet.changeAddresses[0])
-          assert.equal(out.value, 5000)
+          assert.equal(out.value, 15000)
+        })
+
+        it('skips change if it is not above dust threshold', function(){
+          var fee = 14570
+          var tx = wallet.createTx(to, value)
+          assert.equal(tx.outs.length, 1)
         })
       })
     })
@@ -440,11 +446,11 @@ describe('Wallet', function() {
 
     describe('when value is below dust threshold', function(){
       it('throws an error', function(){
-        var value = 5429
+        var value = 5430
 
         assert.throws(function() {
           wallet.createTx(to, value)
-        }, Error, 'Value below dust threshold')
+        }, /Value must be above dust threshold/)
       })
     })