throws error on insufficient fund

src/wallet.js

@@ -203,6 +203,8 @@ var Wallet = function (seed, options) {
           break;
         }
 
+        checkInsufficientFund(totalInValue, value, fee)
+
         this.sign(tx)
 
         return tx
@@ -214,6 +216,13 @@ var Wallet = function (seed, options) {
       }
     }
 
+    function checkInsufficientFund(totalInValue, value, fee) {
+      if(totalInValue < value + fee) {
+        throw new Error('Not enough money to send funds including transaction fee. Have: ' +
+                        totalInValue + ', needed: ' + (value + fee))
+      }
+    }
+
     function estimateFeePadChangeOutput(tx){
         var tmpTx = tx.clone()
         tmpTx.addOutput(getChangeAddress(), 0)

test/wallet.js

@@ -448,6 +448,16 @@ describe('Wallet', function() {
       })
     })
 
+    describe('when there is not enough money', function(){
+      it('throws an error', function(){
+        var value = 1400001
+
+        assert.throws(function() {
+          wallet.createTx(to, value)
+        }, Error, 'Not enough money to send funds including transaction fee. Have: 1420000, needed: 1420001')
+      })
+    })
+
     function fakeTxHash(i) {
       return "txtxtxtxtxtxtxtxtxtxtxtxtxtxtxtxtxtxtxtxtxtxtxtxtxtxtxtxtxtxtxtx" + i
     }